In reply to Bootsy:
Hard to sympathise with that.
If he was showing signs of severe AMS at least 250m below the summit, they should have stopped and turned around. People do NOT recover or even stay on a level if they are that bad.
Kenton "I could not as a mountain guide safely take him down"
Actually that is what you are supposed to do, but you should never have taken him up that far with those clear warnings. Really, really wanting to climb a mountain is not an excuse, I have recently really, really wanted to climb a 4000m peak, but my partner was not well and was clearly not going to recover at altitude. So I promptly turned around and took them down.