Okay so I am in need of some advice regarding my nephews.
A bit of backstory my sister (who has 3 boys) was in a relationship where the dad of the 2 younger boys used to financially, mentally and sometimes physically abuse her. It ended with a court case that he was found guilty (thankfully the physically wasn't too severe) and they went their separate ways. My sister has been chipped away so much that she cannot be on her own so she ended up in a new relationship very quickly and he moved in pretty much straight away.
Fast forward to now, she is expecting another child with this new bloke and I am increasingly getting worried for my nephews. The eldest spends every other week with his dad so he gets time away, but mainly my middle nephew (he's 8), he has incontinence problems and he can be a little violent to his older brother (he has grabbed him round the throat before) but my sisters new bloke is nasty to him. My nephew flinches every time this bloke makes sudden movements near him, the other day in his words he "tapped" my nephew across the face, I didn't see but I heard it as we were outside and it sounded like a twig snapping so I don't believe it was a tap. Even my daughter said he slapped him and he told me daughter that she was going to get him in trouble saying things like that. Making my daughter out to be a liar, which I don't appreciate.
I have called social services on my sister before and I have also questioned my older nephews before and it was all thrown out because it wasn't done by a professional they said it was coerced. I don't want to be shut out of my nephews life (her ex kept me away for weeks because I went against him once) and with a new niece or nephew coming I'm worried its going to get worse to my nephews as this is the blokes first ever child. I am unsure what to do and I have been having battle after battle in my head playing it out, the last time anything came up of him abusing the kids he talks himself out of it, "I have never hit them", "it's only a tap" etc. I think my sister is scared to go against him due to previous relationship so I can't get her to stand up against him, I've tried and she says "there's no point he won't listen"
Basically, I'm just typing this out here in the hopes that I can get advice and strength to do what I need to do, I'm not making excuses abuse is abuse I know that but thankfully it's not severe physically but mentally I think it is, not to mention my middle nephew was force fed by his own father when he was 2/3 years old ( I think that contributes to his problems now). I'm just begging for someone to help make this clearer for me where I can still see my nephews but I don't need to worry that they are getting hurt.
Sorry for the long post it's a lot I know, this is my Hail Mary before I call I just need whatever information I can get.
Thank you in advance for any info.