I'm confused. You said that the counselor diagnosed you with autism, then that "you don't know if autism makes him rude"...?

Aside from that part, I totally agree with everyone else that you need to report him and find a new therapist. Unfortunately mental health professionals treat teenagers this way a lot, in terms of being overbearing and pushy. It's a little bit different, but when I was 16 I informed a psychiatrist that my mother has AIDS and he acted as if I was making that up because it wasn't in my file. It felt terrible to be treated like a criminal /liar because of my age.

I think mental illness and trauma is just now starting to be understood better, but people (professionals included) are more reluctant to accept these issues in children and teenagers, instead of just writing it off as a discipline problem. It's really unfortunate.