Me and my sisters relationship is over UPDATE: Got in touch with my nephew

According to my sister I just ruined our relationship. Her daughter now lives with me. This is all because her daughter cane by to see me. She's 13. It was just a niece auntie day. She started telling me how my sister just seems to hate her now and over the past few months she hasn't felt like a mom. She just feels this strong hatred. I told her its probably not anything and she may be overthinking it. When I took her home, me and my sister sat outside and smoked and I told her what my niece had said and maybe she should talk to her. She told me her daughter is trying to ruin her relationship. I asked how. She's been with her boyfriend for almost a year and I know my niece doesn't like him, so I my first guess was she's been giving him attitude. My sister says her 13 year old daughter is trying to seduce her boyfriend.... Let that sink in... I asked wtf she was talking about and she told me to promise not to tell anyone. I said ok. She believes her boyfriend is attracted to her daughter, who is 13, and that she's been trying to seduce him. I told her she's being a crazy bitch and why would she think that. She admits to finding videos on his tablet of her daughter showering. I start yelling asking why she didn't call the police and she said she's not sending her boyfriend to jail because her daughter wants to be a slut and try to seduce him. She believes that the only way he developed a sexual attraction to her was by her acting like a slut in front if him. Again. She's 13. She doesn't even have boobs yet! I told my sister she is being stupid and her boyfriend is a pedophile but sbe says she doesn't need my opinions on her love life and told me to just leave her alone. Leaving scared me because my niece is in a house with someone taking videos of her showering. I ended up calling CPS and the police. I was the only one my sister told so she knew it was me. CPS got involved very quickly. The next day I'm getting calls asking if I could take my niece in because my parents couldn't and her dad is in prison, so I said yes. Also my niece isn't the only child this sicko had on his tablet. My sister knew it was me and cussed me out for getting her boyfriend arrested. Nit getting her daughter taken away. Getting her boyfriend arrested... She said she thought she could trust me and I'm no sister and i ruined our relationship. My niece is very confused about everything. She had no idea he was recording her and she hadn't been touched by him thank God!

Here's another thing. My sister has an older son who she sent to live with his dad. She told us it's because he was spreading lies about one of her boyfriends at the time. So she sent him away. My niece hasn't seen her brother in years! He should be like 19 now and I'm wondering if one of her boyfriends did something to him and she just said he was lying and sent him away. I want to try to get in contact with him and maybe even reunite them. I'm just glad I got my niece out of there before something happened. I really hope my niece gets to stay with me Bbecause if my suspicions about what happened to her brother are right my sister has a habit of dating pedophiles! Please pray I can get permanently guardianship.

Edit: I was able to find my nephew on Facebook and message him. I told him the situation and we talked on the phone. He was really mad but relieved I got her out of there before it was too late. He opened up a little and my suspicions were correct. My sisters old boyfriend did molested on him and he was sadly raped a few times. He said he told her three times and the third time she sent him to live with his dad because she couldn't handle him anymore. I started crying and apologizing that I couldn't save him. He said its okay and he's moved on with his life. He also said he would love to see his sister he's just busy with school right now so we are trying to find a time they can reunite. He turned out amazing though. He goes to Stanford University is studying to be a Doctor and he wants to be a surgeon. I'm happy he didn't let what happen to him stop him. He also talked on the phone with my niece so that was heart warming. Also as for custody my sister isn't really fighting to get my niece back. She's more worried about getting her boyfriend out. It terrible for my niece that her mother is doing this, but I got a good shot at permanent custody!