By Joe Parlock on Polygon:
I racked my brain to think of games featuring autistic characters that have stood out to me, and four came to mind. All of these characters are different kinds of people with autism, and some of them can be interpreted as positive representations. They also bring to light the tropes and stereotypes surrounding the condition that made me so worried about people finding out I have autism.
He uses the "person with autism" wording that a lot of people (like me) find unpleasant. But as long as we're now letting women and PoC talk about those kinds of characters in video games, we should also be listening to disabled people's thoughts on how disability is portrayed.
Personally, as an autistic person who plays video games one of my favourite portrayals is in Final Fantasy XIV Online. Your player character is shown talking to people occasionally, but words are never put in her mouth. And her somewhat-muted, frequently nonverbal reactions in cutscenes make her easy for me to identify with.
At any rate, I can't recommend the last game Parlock suggests enough.