Betrayed by my sister but I'm the asshole

I posted a year ago about how I found my sister and ex husband screwing around. Well I divorced him, disowned my sister, they got married and had a child earlier this year. My sister is pregnant again. Her son, my nephew has cerebral palsy, I'm a physical therapist you can guess where this is going.

I haven't been to any family events despite being vaccinated because of my sister. I know my parents are torn but they have no right to force us to still be siblings that went out the door when she had sex with my husband in my house. They won't respect my boundaries so I don't go family events. Apparently my sister has been out of a job because her son requires alot of care, she is struggling and her insurance is crap. My parents are elderly there's not much they can do physically. Not only has she been begging my parents to talk to me about providing physical therapy but also babysitting so she can work. I would be his therapist/baby sitter how tf does that work???? While my nephew hasn't done anything to me for that reason I passed on information as far as medicaid and social security. A friend of mine is a case worker at the hospital I work out of sometimes she was more than willing to help my sister fill out the paperwork.

But nah she wanted it free!!!! FREE!!!!! My parents backed that up, I told all of them to fuck off! My parents won't stop calling to change my mind! I never once got this much sympathy from them when she did this to me! All they did was tell her she wrong, they don't like my ex but still accept him. I'm seriously thinking about selling my house and moving to the other side of the country. Idk how much longer I can deal with this mess!!!