Background is this. Ds is year 4, one of youngest and smallest in class, fairly immature (I think) and not one of the cool kids it would seem. Two incidents of mild bullying last school year, one by boy one by girl. This school year, few incidents already of not really bullying, more like teasing, picking on etc. All been picked up on by teacher and being dealt with.
MIL dropped DS off at school today (a one off) and saw a boy who we all would consider to be a good friend of DS (play dates, birthday trips etc), stamp very harshly on his feet, a couple of times and with an aggressive look on his face (MIL's description). According to MIL, this child's mother was present but she doesn't know if the mother actually saw what happened.
From what I can gather, DS moved away from the child toward MIL but the child followed DS and continued with the stamping. At this stage MIL approached them and told the child off.
Do i need to do anything? Should I follow it up by mentioning it to the teacher? I'm friends with the child's mother - is it ever acceptable for us parents to discuss it and get involved or should we leave it to the children and the teacher? I don't want to make a mountain out of a molehill and I do think that DS maybe needs to toughen up a bit and stick up for himself but at the same time, I certainly don't want DS to be treated this way.
I'd appreciate any advice please. TIA