Child behaving badly when not with parents...should they be told?

[Middleagedmumoftwo]

We live in a cul de sac along with several other families and all get along well. Three of the families have kids who socialise together, two of them are aged 10, the other is a year older and went up to high school last year. According to the other two, when he is alone with them, he is very scathing in the way he speaks to them and swears really badly! You would never think this of him, he's always been a really sweet kid, very polite and well behaved. We were all together at a BBQ yesterday and the family with the "offender" were away, and I suggested that they mention his behaviour to his parents (my kids are older so they aren't involved). If he was my son, I would want to know if he was being rude to his friends (they are a year younger so I think he looks down on them these days, even though they've grown up together). They seem reluctant to say anything as his parents do think he's all sweetness and light and it might cause bad feeling. What do you think?

In your shoes I'd back away and let them decide if anything needs to be said.

I would leave it to the children and not get involved.

Absolutely not wont end well and you are only hearing one side of it .

TBH I expect all 10 & 11 yos to swear like troopers when adults aren't around. If the other children don't want to hang out with him they don't have to. Not sure what the issue is.

They are all together by default one evening a week when the parents get together, so the kids don't get much say in the matter really.

It won't go in much longer- he will be able to stay at home. Probably not surprising if he is forced into it, probably he feels that he has outgrown them.

I had a shock years ago when my eleven year old left his phone on his language was terrible I was disappointed but had no idea and never said a word as he never swore in front of me and still hasn't and he is now twenty.
Thing is you never know what your own children are doing .

Presumably the younger two will be starting high school this autumn and that might see them 'catching up' - then again this seems to be the age when parents can no longer 'make' their DC be friends with each other for their own benefit.