How do I stop my friends DS from hurting everyone?

[Micepop]

Hi, I have a question. I have a summer party planned and there will be quite a number of families coming. We have a problem though as in one of the families there is a boy, aged 6 who is challenging. He doesn't play nicely with other children and someone always end up getting hurt by him within a few minutes. His parents tell him off and get him to apologise but he does it again within minutes. My DS ended up in tears at his own birthday party because the boy ruined something he was making during the party. He has no boundaries when it comes to talking to adults and will shout at them as he would a child.It is very hard for his parents but I don't think they see a problem or at least they don't say anything despite them always getting called in at the end of school for him hurting someone. We are friends with the parents and they are lovely people. We don't want to not include them and obviously is unfair to even suggest it but how do I keep him entertained without him hurting the other children? Even if I were to do something that requires painting for example he will just take one of the other children's paints or brush and shout at them or hit them. It makes our children and all the other children sad. It makes everyone there stressed including us. Any suggestions?