Having been onboard this flight and seeing how things unfolded, it is debatable as to what was the cause for the extensive delay. Given that we were near the final 90 minutes of flight when we landed in YQB, any delay, regardless of cause, would have eaten into the legal duty hours allowed for flight and cabin crew. As it turns out, the entire process of offloading the passenger, performing customary checks, possibly refueling if needed etc. would have pretty much pushed the crew past the duty hours limit. The brake system software issue was a cog in the wheel of events that had a ripple affect during that delay, but the initial cause of everything was the Medical Emergency and hence that is what the primary cause was and the other issues that became apparent were a consequence, directly or indirectly of this. As N1Rotate indicated above, had there been no Medical Emergency diversion, then the flight would have continued to JFK and that is where the brake issue would have been discovered.
Generally speaking, and I may be wrong here, but weather related delays and cancellations and medical emergency diversions are among some of the prime events that most airlines do NOT cover as part of their compensation program to passengers. If you read the Conditions of Carriage of most airlines, they do not guarantee time and date you will arrive, just that they will transport you to your destination. In practice, mechanical failure and delays usually warrant compensation to passengers, though some airlines are more wiley than others to admit this and therefore arrange for pay out to customers. The EU regulations help address this issue, but overall, this is the precise reason Travel Delay & Cancellation insurance exists, it's to provide remedy to customers for situations like this. More importantly, in all my time flying for many decades, if you have onward hotel or airline reservations on separate itineraries and other airlines, and not part of your original booking with airline, then you're mostly out of luck, the airline is not liable for losses for missed onwards flights and hotel reservations deposits etc. as the airlines contract with you is to take you to your destination that you paid them for, not for any onward travel etc. If the airline does give you anything, it will be unusual and probably just a voucher for credit towards future travel.
In the end, this was an unfortunate event and the delays were extensive indeed, but that is part and parcel of travel these days, once in a blue moon these events do happen and travel insurance coverage is the best cure.