Hmmmm my first thoughts’ what’s the function of this behaviour’ a child that’s is distressed, misunderstood,
struggling to communicate, struggling to understand social rules? After all being on the planet for four years doesn’t give you a great deal of skill in dealing with life especially if you have undiagnosed or diagnosed needs. Maybe likely that this poor family will have many things written by people like OP, many things whispered about them at the school gates…. The child will eventually stop being invited to parties, the little kids will pick up on their parents attempts to persuade their little darlings to play somewhere away from little Johnnie …bottom line…. Statistically there will be at least 2 children in every classroom with Neurodiversity, maybe he’s one of them. How about you ASK his experts ( his parents) how YOU can help HIM manage the party. - discretely asking all parents via text
“hi, thanks for your response that you are coming, please call me or text me if your child needs anything adapted to support them to access this party, such as quiet music, a quiet place to go, an idea of what we will be doing … and let me know if anyone has any allergies. As the children are so small,I'm asking all parents/ carers to stay”
likely your child is going to know the family’s in his class for many years to come,
important you start off on the right foot. I suggest you do a lot more research on invisible disabilities autism, dyslexia, adhd , even if it’s five / ten mins…. Just to begin to appreciate how / why children may run, hit, climb, escape, swear, bite, alongside…. Educating thier peers that they are brave, strong, courageous, to be admired, inspiring, clever, see the world often from a different perspective and can teach many things they didn’t realise they needed to know…. In your case, compassion, to become more open minded and to educate yourself and be grateful that you may likely never have to face the struggles that is likely of this “ little horrors” family. Good luck with the party.