Tough situation with my sister

First I have to go through the whole story. My sister had a falling out with me and my family two years ago because she felt that as a 20 year old she should be able to sleep over at her boyfriends house but my dad disagreed. (It’s also important to note that she had been lying to them for months about being with him at night and then breaking the 1am curfew they had set, on top of leaving her campus to come visit him which is a long drive and paying for al the gas with my parents credit card, etc.) A combo of miscommunication between my parents where it made it seem like yes she could sleep over at his house while living at my parents when my dad absolutely did not want that, led to a big fight where my parents told her that if she wanted to sleep over at her boyfriends house then she could not stay at my parents house since that’s their (mainly my dads) rule that he won’t bend on. They were willing to help her find her own apartment but she left that night and moved in with her boyfriend. She now says that she was kicked out of the house but I disagree because we were all willing to help her get settled first not just have her leave immediately. My sister stopped talking to us for about a year although she always talked to my grandma who supports her no matter what she does. It hurt that she cut us off but we never truly cut her off because my parents were still paying for her car and her car insurance and I even got her a job at my work. Things somewhat got better as she slowly started talking to us a bit more (first because she had no choice because she hit a parked car and my parents had to pay for it but later it was slowly trying to mend the relationship). When she got her first “big girl” job and moved about an hour away the relationship got a little bit better as well. There was still conflict because know one wanted to discuss the fight that had happened a year before by then and my sister still wasn’t paying for her car so my parents told her she needed to trade it in for something she could afford (it was a brand new car and my parents were frustrated paying for it for so long). My sister’s job turned into a nightmare and she ended up quitting and got another job at a grocery store which is great because then the pandemic hit. Around this time we realized that her boyfriend who has been moving with her, never was put on the lease which my parents had co-signed for them to get it. It was a promise that my sister made to my parents because he has a mental illness which has left him on disability his whole life. So things would get tense again. But for the most part my parents and her just ignored the issues and pretended it was okay. Nobody wanted to talk about it. And then my sister moved to another job which a month later we found out that it was because she was pregnant (she also got engaged because of it). She ended up getting fired from her job and wanted to move back to our hometown. She broke her lease and moved in with my parents for a few months while her boyfriend moved in with his parents and then they moved into a new apartment together. They also bought a new dog. I got my manager to rehire my sister and things seemed to be getting better between my parents and my sister. My sister had her baby and while she was in the hospital she asked my parents if her and her now fiancée could stay with us for a few days because of issues with a neighbor at their apartment. They agreed that they both could stay for the weekend that they had asked for. It’s been nearly 3 months since then and they and the baby are still here. Don’t get me wrong that I love having my nephew around but things are tense. There have been fights between them and my parents. Neither my sister nor her fiancée have jobs. They contribute through his food stamps and disability checks. But I don’t think this can last for long. And the part that I have to ask about on here is that she tries to talk to me about her issues with our parents where she feels like she’s been attacked for the last two years and how she hates them. I don’t agree with her but then she gets upset when I don’t agree with her or I pushback on something she says like when she mentions she was kicked out or that they’ve abandoned her. They don’t agree with her and her choices but they never took her car or stopped making payments. They still co-signed her apartment. They threw her baby showers and even let them stay with them again even though they don’t like it. And worse, today she asked me what my problems were but my only problems besides normal college stress is that having her around stresses me out because I have been caught in the middle between all of these fights for two years now and no matter what I say, I can’t voice my real thoughts without being hated and ignored for a few days. I don’t know what to do. I was even looking for apartments because being so near her all the time stresses me out. But I really don’t want to move out because I’m in a good spot with my parents and I like being here. I’m just frustrated and don’t know how to handle this anymore :(