I’m wondering since your child has a diagnosis of Autism has he ever had ABA therapy. If not ask your child’s provider , case manager or social worker. Easter Seals provides this to children but they need to be referred. I do not know you state or county area, but also many communitys offer therapy and counseling, some even come to your home, to help. Search under free in home therapy in my community, or again speaking with a social worker may help. I sincerely feel for you. I am a mother of 6 children, mostly grown now, but know first hand how these disorders can impact not only the child but the family. I also work in pediatrics with this particular population of children. Keep in mind, he may want to control himself, but some of this may be out of his reach at the moment.
Hope this help in some way. Take care.