Didn't he just find/report a bug in the multi-gpu case? Then have a melt-down after an AMD engineer sent him a fix a couple of days later? I think you are overstating his contributions, in fact it's not clear to me he made any.
I've worked on public software before, and it's left me with an extremely low opinion of this kind of behaviour, and the kind of people that show it.
Gfx drivers are complicated, long term projects. They're not something that get fixed with a phone call.
He found a bug, and made a bunch of noise about it. No need to make it more than it was.