Thank you all for your replies.
I’m asking here because I don’t have anyone else I can talk to about it in real life and collectively you all have a lot more experience of children and relationships than I do.
I had only seen DD or DS before so used child instead.
To clarify the context when I talked about not letting them see each other, I meant at each others houses out of school. DC and friend will be at the same secondary school and currently see each other at school every day as well as at paid for activities. It’s a small community where everyone knows each other.
I talked to school about the friendship as soon as I realised there were problems. Mistakenly thought that if they enjoyed each others company outside of school the behaviour in school would get better. Evidently it didn’t have an effect and things only seem to have changed since I directly approached the mum who was horrified by friend hitting.
I worry about DC and future relationships and that this could be a model to become the abused or an abuser as an adult. If this was an adult relationship it would be clear and I wouldn’t be asking on MN. On the other hand part of me things IABU because they are children and friend might have learned it was wrong?
Have talked to DC at length about how this isn’t how friends treat each other - compare to another friend ‘have they ever hit you, called you names or made you feel sad?’ ‘No’ ‘that’s a good friend’. Since then DC has been more open with telling us about bad things happening at school (other kids) and assertive in saying that they don’t want someone else they previously considered a friend to play with because of something they did, which is great.
I just want DC to be happy and confident. If DC never wanted to see friend again I wouldn’t be posting here, then I could just say to the mum that he doesn’t want to play anymore.
The thing is DC wants to invite friend to his birthday party and has been asking if they can play and has been very stressed about not being able to invite friend.
I’ve been checking in with DC every day to see if there’s been anything unpleasant going on with friend and there hasn’t. At the moment DC is accepting the line that friend isn’t a real friend and you can’t play with him but I worry as others have pointed out he will resent this later. Hoping to counterbalance this by promoting healthier friendships with other children.
I am a ‘wet blanket’ and I know I’m part of the problem. Consensus seems to be that I need to grow a pair and keep DC away from friend.