That is an emotionally appropriate reaction to a person who is harassing so I wouldn’t blame him- Id say next time he go to the nurses office and say I need to go home because the school is making me sick- then call the principal.

I’m down on schools- now so constructive advice isn’t something I can give- now;). Hang in there...

The OP lives in Tasmania and I think IEP is strictly American. Just talk to someone at the school and get some kind of written response for future reference.

Not surprised this happened, it sad how the school thinks they solved the problem too. It goes to show that they didn't care to get more information. It also shows how they don't understand our kids. I'm glad your son stood up for himself, someone had to, obviously the school didn't.
You need to have a meeting with the principal, the evil turd and his parents, otherwise it will keep happening.