Was this an Involuntary change done by AA and is Compensation due?
 

Absolutely horrible experience with American Airlines Delhi Office - Add to this that the AA Customer Relations would not confirm any action they plan to take.
My Story -
1. Jun 21, 2018 - Booked 2 Tickets on American Airlines for 2 Passengers both 70+ years old (BOM - DFW). 1st Segment on Jet Airways to AMS and then onwards on American to DFW. I had ensured that the flights are only 8 - 9 hours long as both have Arthritis and use Wheelchairs
2. Credit Card was charged and AA showed as Ticket issues. Everything seemed fine and dandy.
3. Jun 22, 2018 - Called Jet the next day to see if seats can be assigned. Jet confirmed seeing the ticket, but stated that the ticket was not issued correctly. Called back AA Delhi Office who put me on hold for a couple of minutes and then said the ticket was reissued. No explanation whatsover. They asked me to call Jet Airways 24 hours later
4. Jun 23, 2018 - Called Jet Airways. It is still an issue.
5. Jun 24, 2018 - Called Jet Airways. It is still an issue. So called AA Delhi office, they claimed that the ticket was fine and Jet Airways had a glitch. They would not come on a Conference call with Jet. Asked me to call Jet.
6. Jun 26, 2018 - Called Jet Airways. It is still an issue. Called AA Office in Delhi and they kept the same story.
7. Jun 28, 2018 - Called AA US Office to see if they can figure out. They could not figure out either. Again called AA India office. One of the agents assured that everything was ok and Jet was having problems (that was not true) and that I should call the AA office 2 days before the flight and AA Office will assign me seats and that will confirm the tickets.
8. July 29, 2018 - Called AA Office. They would NOT assign seats. They asked me to call Jet Airways to get seats. I reminded them what they had said before and they said "we have confirmed internally with Jet and you are set. Just call them for seats". Called Jet and they still have the same issue. After that tried calling AA India Office who simply refused to pick up the phone.
9. July 29, 2018 - Called AA US Number. A nice Agent finally looked into the issue and gave me an option of going via Cathay Pacific as they never had any codeshare issues with them. I had no option but to agree as sticking with Jet would have been a nightmare had the Jet folks not let the customers board. The ticket was then issued, but again same thing as Jet, the ticket was not reflected in the Cathay Pacific system. Called AA US Office 2 hours later and they said to wait.
10. July 30, 2018 - Called AA US Number about 24 hours past the ticket reissue and they then contacted one world and said that something had to be fixed in the original ticket and then it finally started showing up in Cathay Reservation.
11. July 31, 2018 - Travel date. Started as two 8 - 9 hours journey, ended up with 6 hours to HKG and 16 hours for the next flight for two patients with Arthritis.

Now the next step - Filed a complaint with AA Customer Relations asking them to confirm that action was being taken against the callous behavior of the AA Delhi Office and a suitable compensation for the hassles endured.
Customer Relations responded back saying:
1. We cannot confirm any action taken against anyone. That is our internal policy. Basically saying that "We will behave whichever way we want, nobody can touch us and we are not answerable to our customers".
2. No Compensation is due as we accepted another flight. So basically, it was almost like someone making you accept something at gun point (we were not given any other options) and since we accepted it, there is no liability on part of American. I was thinking this was an Involuntary change (I did not request it) and hence there should be compensation. Is that fair?

You paid for travel from BOM-DFW. You received travel from BOM-DFW. What compensation do you believe that you (or the passengers) are entitled to?

I don't mean to be unsympathetic, but compensation for what? You set up an unusual requirement, that the passengers would have no problem flying two segments of 8-9 hours with no overnight in between, but one flight of 16 hours would be unacceptable for them. I am not sure the systems allow for this criterion in judging the validity of a complaint or determining compensation.

Typically, if you have an itinerary like this, you want a full service travel agent (and they do still have those in India) put it together, rather than an airline that doesn't even fly to India. Anyway, there was some issue with ticketing, and they gave you an excellent alternative (excellent in the sense of only 2 flight segments). Again, airlines can't handle or even understand individual requirements such as "can only fly 8-9 hours per segment" or "cannot fly during full moon".

Move on. Sometimes ticketing can get hung up across different carriers and different systems. Yes it can be a pain but nothing to expect compensation from. It was very generous for AA to rebook them via HKG. And of course AA is not going to tell you what action they are taking against the India office based on your complaint. But I can: none.

When AA indicated they could put them on CX via HKG, why dd you agree, knowing the flight and layover lengths?
AA can't force a booking via HKG unless you approved of it.
Why didn't you just cancel and book through Jet at that point, or soon after they indicated a problem?
Additionally, AA is not going to give you information on internal HR actions taken.
I agree, you didn't the best of service, but the major part of the trip was on Jet, so I don't quite understand why you booked via AA in the first place?

Vowww !! Seriously?
The ticket was supposed to be issued and once ticketed, I should have spent my time without the sleepless nights.
Do you realize how many calls and how close to the flight date the issue was resolved?
Finally, would you accept if instead of of 5 hour flight, American takes you thru a 15 hour flight and lands you at the same destination? I guess per your logic, they could have taken me in a train or bus taking 40 hours instead of a 5 hour flight and that would be ok as they took me up to the final destination.

The AA Office is actually a Travel Agency owned by American.
As for 8 - 9 hours each, I hope you read the part around Arthritis and not wanting to have a 16 hour journey.

There are 4 segments in this trip. 2 onwards and 2 return. Only the 1st was on Jet. The other 3 were on American and British.
And yes I approved the move to HKG, because that was the only option given OR stay with Jet and play our luck. What am I supposed to do? Hope that some magic happens and Jet lets us board (when they had clearly said that they would not let them board)
Jet was not selling this itiernary. It was sold by AA.
Also, why would AA let me cancel the ticket as AA kept saying the ticket was fine from their end.

I am very familiar with arthritis. I am not familiar with a type of arthritis that allows two successive flight segments of 8-9 hours each, but does not allow a single segment of 16 hours. What qualitatively new medical issue occurs on a single long flight but not on two successive flights? In any case, the relevant issue is what the airline will understand, and they will not understand this fine distinction. They put you on a much better airline than Jet Airways or American.

Plus, as already pointed out, if you don't want a routing you should not agree to it. You could have gone to the airport early and seen if there is a problem; 9W's phone agents are incompetent.

I do understand that you did not get what you wanted, and the airlines were not able to solve it to your satisfaction. Is it 9W's fault, or AA's? We'll never know. What we do know is that the AA-contracted agency gave you a good alternative, which you took.

The ticket was not fine, otherwise AA would not have changed it. At any point did you ask them to cancel it?
It doesn't matter whose end it was fine at, if it was not fine all of the way through. If there was a problem with the Jet flight, then it was not "fine" and you were entitled to cancel with a refund

I repeat:

The AA Agency in Delhi (note it is a Contract Travel Agency) insisted it was fine. The AA Exec Plat Cust Service Agent is the one who agreed that it was an issue and finally changed it 40 hours before the flight started.
The AA Agency in Delhi also assured that the ticket was perfectly ok and that they would assign me seats 2 days before travel. In this case, why would I cancel my ticket???

OP has changed the story. Looking at the lengthy first post, it is entirely unclear that there was anything wrong with the Jet reservation, simply that Jet would not recognize it. Thus, AA came up with an alternative. While it is fun to blame AA, it is more than likely Jet playing silly bureaucratic games.

The reroute was either acceptable or not. If the parents have medical needs which preclude a flight exceeding 9 hours, then it was irresponsible to accept the reroute. If there is no such medical requirement, this is simply something made up. Either way, there is no compensation due.

AA rerouted OP's relatives on a likely much more expensive ticket and that is the end of it. If they were medically unfit for that routing, it was a simple "no". But, whatever it is, it isn't OK because AA tosses a few miles.

I think move on is good advice (compensation for what?), but, "it was very generous for AA to rebook them?". I wouldn't call it generous of AA to ensure their costumers were able to fly between the two airports AA sold them tickets for.

Well, the OP's initial post indicated that this was nothing more than a combination of incompetent phone agents and Jet not being able to assign seats, both of which are unfortunately totally normal, so it would have been very generous for AA to offer a full rebooking at no charge. However, as he/she has revealed a few more details of a deeper ticketing issue, then I agree AA did what it should have in the rebooking.