Probably there is lots more that can be done. Probably he could be better supported in school, by training his TA better. And training his teacher better. His TA should have been able to prevent him getting that violent in the first place. Perhaps by removing him from class before he got violent. His teacher should have been able to provide a calmer environment that suited him better. The ASD Outreach team should have also been able to provide suggestions and help for the school and child. Without knowing an awful lot more details about, nobody can say whether school were doing everything they should have been or not. It really depends on the kid.