Bit nervous to post in AIBU as I've been accused of being over invested in the past (probably somewhat warranted).
DS aged 11 is in an intermediate school (years 7 & 8). This years he's been playing everyday with his oldest best friend since age 3 and a boy new to our area. I'll call them A & B.
A few weeks ago I was talking to the Mum of another boy in the same class who DS knows through a sport. She asked if DS was happy at school and I said yes he's really enjoying it. She said her DS (I'll call him X) was having a really tough year as a boy in his friendship group was excluding him and being nasty and X's oldest friend was always playing with this mean boy now etc. My DS and X have always got along well but are in different friendship groups at school. X's friends are sporty "cool" kids whereas my DS's friends are more ordinary "not so cool" kids. She asked who DS plays with and said maybe she should tell X to play with them. I said of course they're really nice kids.
So, a few weeks ago I've started to notice that DS is hanging out with boys from a different class now and when I asked him if he wanted to have A over one weekend as I hadn't seen him for a while he didn't want to, he asked for a boy from this other class. After a bit more digging it turns out X has been excluding him and according to him A & B do nothing. He said yesterday he asked them at lunchtime what they were doing and X said "none of your business" and this is happening all the time. It's especially upsetting that A does nothing to help.
I said I'll talk to X's Mum (not accusingly as I'm aware I only have one side) as she'll be able to have a conversation with him about empathy as he's doing to DS exactly what happened to him but he doesn't want me to. He wants to sort it out himself.
My AIBU is do I do it anyway and tell her that DS didn't want me to but I felt I needed to or let him try to sort it out himself (and if he is unable to sort it out then talk to X's Mum). I don't feel there is much point talking to the school as X's Mum tried that when he was being excluded and they don't help at all. DS was upset telling me last night and on brink of tears so I know it is getting to him.