I'm Nc with my sister - best decision ever!
You don't have to see her again or have anything more to do with her.
I'm also a Lp I managed without childcare from my parents millions do. To be honest I wouldn't want my DC being the next generation being indoctrinated into the dysfunction. Pay for childcare or work out a reciprocal arrangement with another mum.
I don't speak to or about (irl) mine any more. I don't go to my parents house but then I'm lc with them too. If I see my mum it's at mine or in town.
What the hell has she got to be snobby about? She's still living at home and they're supporting her! Even if she did it's an unacceptable way to behave.
Tell her you no longer wish to have any more to do with her, then block her on everything. Mine threatened to come to my home. I had texted her I wanted nothing more to do with her and why (inc her assaulting me) so I felt confident in saying if she did I would consider it harassment and contact the police. That if she forced me to do that I'd be pressing charges on the assault too. As a result she didn't turn up.
It's my 3rd time going Nc with her, the first 2 I was persuaded to give her another chance by my mother. This time was different. Partly because I was very calm and very clear that I no longer wished to have anything to do with her nor even hear about her. Partly because mum witnessed the tail end of the assault. So could no longer deny to herself that my sisters treatment of me was excessively bad. Prior to that she was all "we'll all siblings fall out sometimes".
Mine has made similar digs. In all honesty I believe she has very low self esteem thus feeling the need to put others down. She does it with others too - it's why she's no real friends or a relationship either.
Pps are right though - what the digs are about, even the reasons are irrelevant, the point is she wants to hurt you. It's not even indifference. So don't give her the opportunity. People like this don't change.
It sounds like she is at least your mothers golden child if not your fathers too. Have you read up on toxic family and golden child/scapegoat scenarios? If not I'd definitely recommend you do.
"He is right because the both of them change facts and make out you’re lying" he's an enabler which means he isn't your friend either. You also need to google gas-lighting - that's what you're describing here it's a particularly nasty form of emotional abuse.
Your mother IS taking sides in not dealing with your sister - she's taking your sisters side. I've had similar conversations with my mother.
Honestly I highly recommend Nc with sister vlc with parents inc not leaving children alone with parents. People who golden child/sg their own DC tend to carry that through to grandchildren too. Mine certainly did. I think you'd find it a huge relief.