My 11yr old as just recently been diagnosed ASD. I understand him a bit better now we have the diagnosis, but its still not easy at all.
Primary school was very hard, the teacher who did the sen really helped me with the diagnosis mind, if it wasnt for her help I still dont think we'd have the diagnosis as his symptoms were more pronounced at school than at home. That said mind, because the diagnosis came in the last term of y6 he didnt have the correct support, he had some, but no where near enough.
When things went wrong, he basically got treat like a naughty child, because he was actually autistic he didnt understand what was going on due to lack of support which he didnt get because he hadnt been diagnosed.
The parents of the other children were a nightmare, something needs to be done they'd say, myself and the school would say something is being done.
There was one time it was almost lynch mob mentality towards my son , two parents who's kids had bother with my son, got together with a third and talked about how they would approach the head about him, one of them did and the head put her in her place saying that it was her job, with the support of other staff in school and me that would deal with him and she was to take a step back and let the school deal with it.
Thankfully it did settle down, maturity in my son helped a little along with me understanding autism more. The other parents views of a difficult child can be awful, even with diagnosis, one said about another two students who were ASD that they were crackerjacks and shouldnt be at the school was awful.
The worst bit about ASD can be other peoples misunderstanding about it and inability to deal with it.