The most unfortunate thing here is that the Captain became ill whilst operating an aircraft. If he had his medical episode on the ground (in pre-flight or whereever) it would be much, much less of an issue. I only want to make these comments;
1. I hope he gets the medical help and support he needs
2. Well done to the FO/PF for realising there was a danger to the aircraft and dealing with it professionally.
3. I work in a high stress environment (a trading floor in an investment bank). I've seen people break down VERY rapidly and VERY completely. I've also been lucky enough to work with them again, many months later, when they have had their medical condition stablisied and the underlying factors of the break down (root cause) corrected.
There but for the grace of god go I. Some posters in this thread need a very long hard look at their attitude to a fellow human.