How to tell parent I know and entire town what they have being doing?

Long post and idk what to do any advice needed on how to approach this. Sorry for grammar mistakes English isn’t first language.

So my mom is single women 55y she lives by herself in her own apartment.Im married with kids and only child and we don’t live on same continent (dad died when I was young and they were divorced).And I told her she should find someone to have either living with someone or some friend.

Well she did and they started living together but after couple months she returned to her apartment saying she can’t anymore.Okay no big deal.

Now husbands brother and SIL went there and people in town were saying (that is small town and almost everyone knows everyone) to them how some dude is saying he was effing her while she was forging some plants. His words “every time I want to have sex I go there do deed with her and just leave her there naked” and apparently some people sa that too.And how she was sending some man naked videos (omg I want to vomit while I’m writing this). And husbands SIL saw that video (man in question is married with kids and grandkids). And everyone talks about her in town.I want to go there for visit but after this idk how can I see anyone in eyes while they know everything.

They are talking how she is whore and if you don’t ask you will not get.

She wasn’t like this while I grew up.She gave everything to me and still I shouldn’t be holding hands or do anything to embarrass her.

Now how to tell her that people are talking and if she wants to do that she should be more careful.

Please please any advice is needed idk what to do.