Ugh. Long story short, I was Facebook-stalking my semi-estranged sister today and noticed that one of her FB friends had the most pedophile-y photo you can imagine. I clicked on his FB pages and his movies and books favourites are full of porn. This is on his main page, no privacy settings, so all the internet can see. At the very least, this man has a poor grasp of social norms.
My main concern is that my sister has the poor judgement to associate with this guy and SHE HAS KIDS. Pedos actively seek out single mothers to befriend just so they can get access to their kids. I don't know for certain what this guy may be up to, if anything, but the whole thing STINKS. (On the plus side, from the looks of it, his tastes run to fully grown women.)
Ughhhh.... what do I do? My sister would blow up at me if I dare criticize any aspect of her parenting. I'm pretty sure my sister was sexually abused as a child (plenty of red flags in hindsight), so it's a very touchy subject to bring up. I don't mind if she blows up at me, as long as she protects her kids but she is quite capable of not doing so, i.e. letting the chips fall where they may, as a weird kind of reactance.
I didn't think it was possible for my dysfunctional family to shock me any more, but here I am.
Certainly he's an idiot or is always trolling for women, but unless there's stuff about children involved that you see, I wouldn't be super worried about your nieces/nephews. Are you close at all to them? If you have any relationship with them, I'd reinforce that you're a safe place for them to come with any kind of information without being specific about sexual stuff.
I wonder if Facebook has any means of reporting this. I doubt it, because frankly, you have no business trolling his site. If you and your sister are estranged, would she even listen to you?