Tbh I think there are two kinds of autism. 'Real' autism, like your brother has, or people who cannot speak, etc. This kind seems to be much rarer, but a tragedy for everyone involved. I read an article (linked here on HN but I can't find it anymore) about someone taking care of such an autistic person and it is heartbreaking.
The other kind I would call 'newest fad' autism that people who are a bit socially awkward label themselves with, and pride themselves with their 'beautiful mind' and their intelligence. Bonus points: They don't have to improve themselves and their social skills because it's a mental health thing and out of their control.
The catalogues of mental disorders (like DSM) say a lot about a society.