Reading this really makes me want to recommend the Norwegian movie Elling - it's witty, completely unschmaltzy and hints at a pretty good answer on what good care for adult mentally challenged folk looks like. http://www.imdb.com/title/tt0279064/ It's streamable on Netflix for the US-based folks: http://www.netflix.com/Movie/Elling/60025098
I'm really curious. What about reading this article made you think of Elling and what you refer to as "mentally challenged folk"? Maybe I'm missing something (I haven't seen the movie, but from the imdb link you posted, no mention of autism)... but it seems to me like you're saying "having autism = being mentally challenged". Am I misinterpreting? I hope so :(
Separately, though, if you ignore some of the connotations, it does seem fair to call autism a "mental challenge".