Very weird family situation

Hello.so I am 36, married with a baby. My family (parents and 4 siblings) are all very intertwined with each others lives and I believe this is because we have had somewhat of a chaotic past. My parents got involved in a very spiritual church when my twin and I were young. All lovely people but it was intense.my mum and dad's relationship was v toxic. Mum self harmed. Tried to leave a few times. Dad struggled with a new business but he didn't help matters as he did a lot of controlling so much that my mum kinda lost herself. E. G. Had no idea if she was on the mortgage. Lost independence. They hurt each other v badly. I did the teenage thing an rebelled but was judged quite badly by the church who were like my family. my twin did the opposite. She became very deeply religious. She would do annoying things like tell me I shouldn't wear make up. I shouldn't date boys because it will mess my life up. Shouldn't wear certain clothes as I'm objectifying myself. I'm a tool apparently in a man's tool box.i shouldn't fill my head with rubbish TV programmes.so we did fight and id end up on a huge guilt trip. Over the years my mum became less strict, she also moved out changed her surname and tried to get a divorce. started to drink and got 5 tattoos in 1 year? My sister moved back in with my dad and she really idolises him. Together they tell the church mum is mentally unwell and that's the reason why she is irrational. Dad is not to blame. Whereas I am quite objective.as a wife and woman I wouldnt be able to cope if my husband made so many false promises, lied, dismissed me. My mum opened up and said the reason she self harmed was because she needed to know she existed. Now I am not saying she is an angel. She did some pretty damaging stuff. Around the time my sister moved back in with my dad, she started telling us she was hearing God speak to her, she aware people were trying to control her with their thoughts. Even telepathically communicating with each other to the point they controlled where she sat in services. I actually noticed this where as my dad was too busy and I told my parents to help her. That's why she moved in with my dad. My mum and dad have never been to therapy. We haven't been known to any services e.g social. Everything is hidden. Even when my sister was behaving odd I was trying to get her professional help but I was limited. Bshe wouldn't accept my parents thought it would make things worse. My mum and dad, 3 years later, now, are trying to give it another go. My sister continues to gaslight my mum and when I kindly told her to not get involved if they do bicker she got upset angry and defensive and told me all of their problems are down to mums mental health. She is unwell. Dad is perfect. I said, surely you can see that it's wrong to just strip someone of their reasons and dismiss their feelings by telling them and everyone else that they are crazy. My sister said I was trying to control her mind. I'm under the impression she thinks it's a spiritual attack because her n my dad in the past have rejected me and what I say even telling me to go back to thr abyss where I came from. They are super spiritual but also lie a lot too but they justify themselves e. G p to local authority. I believe part of my mum's behaviour was because they treat her like she's not human and don't validate her when something is really bugging her. I am not able to have dialogue with my sister. We have no connection. I'd love to talk to her but she does things like give up her job as she wants to be submissive to my dad? Even dad thought that was weird. We get into arguments because she tells me she has facts when I say... That's a theory. It's not a fact. She can't handle that and gets very upset. I am starting to see that I Really don't think I like her. I feel awful for arguing with her. I never intend to and I mostly bite my lip. But she always says things I feel are damaging and tonight I told her that she shouldn't talk about mum in this way as it's damaging to mum, her relationship with mum and my dad and mum. I also told her she was antagonising. She said I was just trying to get into her head, I am rotten and I am rubbish. It's a huge mess I don't know how to have a relatiinship with her. I'm kinda grieving about it because I really wish we got on and I have loved her but she makes it really difficult. I personally think she should leave mum and dad's house. But there is another side of me that thinks she might not cope well being in her own. She has moved out before but u don't think she will be a me to now. Any different perspectives greatly appreciated.