When you say go back to school do you mean High School ? If so, by law your child can stay until he's 21. At least that's how I remember it.

Here is information about post secondary education. Does he have an IEP? Do you think community college would be a good option for him?

https://www.autismspeaks.org/postsecondary-educ...

Postsecondary Education | Autism Speaks

https://www.autismspeaks.org/postsecondary-education

My son is in high school and I was told the same thing, by law he can stay in school until he's 21.

Yes true!