Nephew ran away to my home

My nephew has been in and out of my custody 3 different times. My sister has lost custody of him 4x. He just turned 14. He's been saying he wants to stay here but he's never listened to. My sister is a shit mom. It's the truth. She has always put men before her kids. My nephew's father used to beat on him which is why she lost custody the first time and she would say "He's disciplining him" and "As long as he ain't beating me I don't care." She has left my nephew home alone for weeks. Her excuse was he's old enough to be home by himself but they would have no food. All I've done was document, document, document. And yes I have called CPS on my sister. I don't care if she's my sister. If you're a crappy mom, you're a crappy mom. The men she dates are awful. And she defends them with her whole heart. 4 different men she's dated have been pedophiles and she always defends them. "It was a long time ago." "He's a Christian now" "That 7 year old child was lying." My nephew suffered sa because of one of her past boyfriends. She is dating someone who she moved in right away. The man she moved in did 30 years in prison. So I looked him up. This man was arrested for drug possession, assault, kidnapping and extortion. The very short version of the worst of what he did was kidnapping his 17 year old step son and trying to extort his ex-girlfriend. My sister defended that saying that the ex girlfriend owed him money and he kidnapped a young adult. Not a little child. She has defending people who have killed people. She's a horrible gross person and CPS just keeps giving him back. I'm kind of at the point where I don't even want to call it in because they will bring him back. I just want to give the poor thing a break. A least for Christmas and then try to get CPS to do their fucking job. He ran away to me. I literally have him a room here. My sister gave his bed away to her boyfriends adult brother so he's been sleeping in a sleeping bag. I hate her so much