So my friend turned up at the airport and was told that his flight was rescheduled to 24hrs later and there is no way to get him to his destination that day. Apparently he was emailed but he never got that.

They were nice enough to put him up at the airport hotel for the night but this ruined his vacation as he had 3 non refundable nights booked at the next location of which he lost the 1 night and also his next flight was booked on a different ticket so he could not change it to stay another day. He did not get enough time to see the city + lost one night at hotel + had to waste 24hrs of his vacation in a Bed & breakfast close to the airport.

This was in South Africa so I guess no EU rules come into play. But any others?

Presumably he has travel insurance, either bundled in his credit card or as a separate policy. I have used mine for just such an event several times over the past year (for example when the ash cloud cancelled transatlantic flights).

Yeah he does. But he isn't to bothered about the costs. It was more that the airline ruined his holiday. He was just wanting to know if they should have informed him legally or not.

I suspect the airline will argue that it attempted to inform him but couldn't reach him. I agree it is very annoying when these things happen, but such is life.

A few years ago I had a similar situation on BA LHR-BKK-LHR. The outbound flight was delayed by 18 hours. BA agreed to reschedule my (non-flexible) return CW flight by one day, and Amex covered the (minor) additional hotel change fee.

One thought that comes to mind (and unfortunately it's too late to help your friend) is that we should always check our flight status before heading to the airport. Even if the weather looks fine, there could be any of 134 +/- reasons why a flight might be delayed/cancelled. At the very least it would give one an hour or two head start on finding alternative plans.

He isn't a FF'er so wasn't aware. Trust me I know when my flight time is even changed by 5 minutes

The exact same thing happened to a friend of mine, this year, flying Delta out of Germany. The flight was cancelled and he was booked on the same flight the next day.

What did they do for him? They paid taxi fare back to his house.

After he got back from the US, he wrote to Delta, and got a reply back that taxi fare was all he was entitled, as the flight was out of his home airport. Had it not been his home airport, they would have paid for a hotel.

guess he didn't check into his flight 24 hrs earlier otherwise he would have known this. while it is 1/3 of the vacation, how much did he really lose if he didn't see the city in 2 days vs 3 days?
and, he did buy 2 one way fares as you indicate, which i'm assuming was because of price, so why isn't price/$ an issue now?
this entire thing doesn't really make sense.

Eh! What do you mean? Its simple, he wasn't imformed, he was on a Island where the internet charges were silly and he didn't have his laptop. He isn't a FF so doesn't know about CMT and the other options available to check etickets. He wasn't informed and all I wanted to know was if it is the airlines responosbility to make sure he knows before turning up at the airport. Does it make sense now?

Around �900 as the first nights hotel room was non refundable so he had to pay that.

I book my vacations with plenty of time, that if I missed a day, it wouldn't matter much..

Best to relax on vacation by booking a bit longer, then end up with a situation to OPs friend..