Our son is friends with another kid in his class (he's a bit older) and seems to be quite controlling of him. In October his friend starting telling him that he couldn't play with them (and small group of 3 friends) thankfully the other kid stood up for him and played with him. This went on for a few week or so I believe until he told me what was happening, I then mentioned it to the teacher (not naming the child involved) the teacher and assistant caught them out though in the playground and told him not to act like that.
It happened again in class a few days later when he took items from his desk and started shouting at our son in class, the teacher told him to apologise and put him out of the class. All of this had died down for a good few months until we saw the child at the weekend in a club close to us and he was there with his grandma (whom I didn't know) my son spotted him instantly, seemed OK, the other kid was smiling at him but he was settled at another table with other people who I assumed he knew so I didn't interrupt. I asked my son if he wanted to sit beside him and he said no, I said ok then (he was tired tbh and is very shy generally). I had to pop out to take him and his sibling to the bathroom. We settled in another part of the room and the kid passed us so I said hello and he blanked me (not that i was worried, just thought it strange.) The grandma just sat on the sideines anyway, come Monday the kid started isolating our son again, pointing out differences with his peers. On the Tuesday he shouted at him not to line up with the others and to go away. Our son ended up crying at this. The teacher walked with him to find out what was wrong, he lied and said he was just missing his parents. At pickup they told us he had been crying but they didn't really know why. At home he told me why so I informed the teacher. She said she would speak to the other kid the next day. She then updated me the following day to say she had phoned the parents to encourage him to use kind words with his peers (I'm not sure if my son's name was mentioned or not specifically). We have a class birthday party to attend next week and his parents will be there. I'm not sure if we should still go, or if we do how I should handle this. (I'm not one for confrontation). It seems awkward now.