Brother in law wants to fuck me

Okay so I was chillin at my friends house today, which is my baby’s father brother girlfriend.. so we were just having some girl talk then in the midst of the conversation she brings up her boyfriend (which is my brother in law) so she said he’s been saying some awful things about me, like EVERYDAY.. which is odd because I haven’t done him anything & plus we don’t even communicate none whatsoever. So then she proceeds to say one day he was talking shit about me and she asked him if he wanted to fuck me because he’s been talking about me a lot lately ,, surprisingly he laughed and told her yes! What a shocker! She told him to get out & to never step foot in her door again! (But I’m pretty sure they would be back together) it just hurts my feelings that he could say such awful things about me then admit he wants to fuck me, how weird!

How do I tell my baby’s father this? I want him to know but I don’t want my friend to think I’m starting shit but I feel it’s his right to know so he can decide if he wants to bring him around.

I mean he always wrote me on Facebook messenger saying “what’s up” “wyd” or “wya” but I never responded , I showed my baby father and he says “oh he’s just friendly don’t worry about it”

Now this happens! What to do??

Yes I’m still with my baby father , we live together. We have one kid and one on the way!