How to convince my little sister to move in with us. Please please help

Okay. So. First of all, my sister lives with my mom and I live with my dad. My sister (we'll call her Cindy) comes over to the apartment my dad and I live in on the weekends, but she lives with my mom and goes to school in the city my mom lives in. Reasons my sister should move in with us: *Better schools. My mom lives in a very ghetto area and the schools suck. If she moved in with us, she'd go to a certain school that happens to be one of the top in the state. I went to the middle school my sister is currently at, and it is an awful school. It has a 'D' rating, and the one she'd move to has either a 'B' or an 'A' rating (can't remember which). She'd learn a lot more and have a lot more opportunities academically. *Better area. Like I said, it's really ghetto and trashy where my mom lives. Where we live is a lot better. We live in a college town, so there's a more diverse and involved community. There's a lot more to do and learn. It's a great place, and wayyyy less drugs. Speaking of which *My mom. My mom sucks. She physically and emotionally abused me for years, my brother before that. She has and may still do drugs, and she lets homeless people stay in a house that isn't even hers. She doesn't feed good food. I remember days where she didn't feed us at all. She's a slob with bugs and rodents in her home. She doesn't take care of herself or anything she owns. She leaves to go party in the middle of the night (which would be less awful if her neighbourhood wasn't so dangerous), and when she gets caught she just dumps my sister on my sick grandma. So most of the time, my sister isn't even with my mom. She ditched me and my sister for an entire year and we had to live with my grandma, but my mom still got the child support and claimed us on her taxes. I have trouble even calling her a "mom", because she never took care of us. I don't think she abuses my sister like she did to me and my brother, probably because now she's afraid of being caught. She's incredibly fucking unstable and shouldn't have children under her care at all. *Better living conditions. As mentioned above,my mom's house is awful. My mom doesn't pay her bills, so my gramma has to instead, which is milking my gramma dry (I think she may kick my mom out soon). Sometimes, she doesn't have electricity. And sometimes, she doesn't even have hot water. The house is completely trashed. Nothing is clean. It makes me think of Annie Wilkes' house in the book Misery, when Annie goes into a really bad depressive state and trashes the house with food and dirty dishes all over. It's disgusting and nobody should be subjected to living in that mess. I'm a neat freak, so I keep it hella clean over here or else I'd lose my sanity like I did living with her. The problem is that Cindy doesn't want to live here. She has animals at my moms. She knows that they'll die if left alone with my mom. The poor dogs' ears are already bleeding from fleas, and the cat is losing all of its fur. My sister is probably the only reason the damn things aren't starving. She also doesn't want to move schools. She has friends at her current school. She also has a girlfriend, who goes to a different school right now but might move back to Cindy's school soon. Also, you might have guessed this, but my mom is very negligent. My mom doesn't care enough to discipline my sister, so Cindy kind of gets to do whatever the hell she wants (which isn't good for her anyway). For legal reasons, my dad can't take my mom to court like he should, so if my sister moves here it has to be her choice. But she's only in middle school and kind of overemotional, so she doesn't really understand where her priorities should be and that living with my mom is toxic. She's said something about moving with my gramma so she's still close to her animals and at the same school, but my gramma is too old and sick to have to worry about raising a child. We can't do that to my gramma. At this point, I'm kind of desperate. Is there ANYTHING you can think of that I can say to my sister to convince her? (sorry if this is rambly, it's an emotional topic for me + I'm hopped up on caffeine rn)

It's really too bad that the court system turns a blind eye to this sort of thing. Tell your little sister that this is for her health and own well being. What about bed bugs? There's a possibility that she living in such a slovenly condition that there's bed bugs. Yuck! I don't know about her pets or what you could arrange with your dad. Maybe a temporary shelter such as a vet to check out Thier condition