I mostly agree with you LMS, I see valid points from both sides. Sure it could have been a one off, maybe the teacher was particularly stressed that day, but that doesn't make it "ok" to speak to a student like that. It is drilled into students that the school yard should be a safe place for everyone (or at least it was drilled into us). If it was another student who said it, there would have been repercussions. The same should go for the teachers.

The other thing to consider is maybe it's not a once off? It may have been the first time Dianne's son was exposed to it, but who knows what he's said to other students before. If no one does anything about it then he will continue to get away with it.

I wouldn't suggest that Dianne's son speak directly to the teacher, but I think some kind of communication needs to happen, maybe a meeting between the principle, the teacher, Dianne and her son? That way there is someone present from both sides and everyone can (hopefully) get a full picture of what happened and find an appropriate way to deal with it.