[mikester]

We had an extremely similar situation at school with my oldest who was 9 at the time last year.

Him and another boy who had been very good friends all of a sudden no longer got along. It wasn't just my son though, the other boy was having trouble with all of his relationships and he is also on the autism spectrum. We had a teacher who was watching out for things in class and started volunteering at recess and lunch because the recess and lunch monitors were not doing a good enough job and things were escalating.

We were and are pretty close with the other kid's family. My wife and his mom are very close friends. Me and the Dad are friends too and up until their son started having problems the boy was in our Cub Scout den where I am the Den leader.

Meetings at school, he dropped out of scouts, boys were basically directed at school to stay away from each other but in the end they reorientated themselves and are again friends. Not really as close but pretty good and it seems to have normalized.

Hug your son. Stand up for him at school. If the other kid is challenged as you say be understanding of course but only to a point with the school. The school needs to provide the protection for both boys and if it can't then it needs to do something before you have to escalate in the name of protecting your son. I would make friends with the administrators but be very stern with them at the same time.