So I had DH 2 sisters and their husbands and kids over last night for xmas dinner, all went fine and one of the BIL is a bit of a tool but was ok until about 9pm when his 13 year old DD and my 5 year old DS were jumping on the trampoline, we heard DS crying and I said what happened and he said his cousin jumped on his arm and she said yes sorry it was an accident , DS said no it wasn't and hit her on the arm when she tried to console him, I yelled out to get off the tramp and don't hit your cousin it was an accident, so he gets down in that ugly over tired cry and starts walking over to the table we were sitting at holding his arm and on the way to me he passed BIL who grabbed his arm , pulled him close and said " if you ever hit your cousin again I'll hit you even harder - do you understand me " DS said yes then burst into more tears and ran to DH who was sitting next to him
My initial reaction, apart from shock was to say in a very cranky tone
" don't you ever touch or threatened my child , I can't believe you just did that, if you threatened or touch my child again I will have you arrested " he said "he needed to be told" I said " he's 5, it's xmas he's overtired and I already told him" he said " well now he's been warned" I said " get f 'ed" and he sniggered , I then said "as a matter of fact get out of my house" to which he got up and left
DS was over to me by that time and was still crying and I just hugged him and said not to worry BIL is just being silly , he calmed down after that and my other SIL took him and the little kids for a bath, my poor SIL whose husband it was looked mortified , we get on really really well and I said I'm sorry I probably shouldn't have asked him to leave but I can't believe he threatened DS, she said either can I Im so sorry he's an idiot , she left with her girls , DH said I beat him to saying something and not to stress as he was in the wrong - I think my initial reaction to ask him to leave might have been over the top but I still standby what I said - I don't hold grudges and he is welcome in my home but don't touch my child again!
Did I overreact and what would you have said/done ?
ETA - we tell each other's kids all the time , no hitting, no yelling etc and I have no problem with that , especially if DS is doing something wrong