I have spent a fair amount of time with autistic children in my life and I can say that, in even the most extreme cases, video games are something they tend to pick up. It would seem strange tho for a MMO to be the game of choice, simply because the nature or autism deals with blocks to social communication. Using it as an excuse I cant see in anything more the more mild cases. However I'm not professional in any way, and this is just what I have observed.