As the title says my older sister is again causing drama over stupid stuff. She's our dad's favourite and she knows it. I message dad and call him with no response and I'm quite fed up of it yet he drops everything for her and helps her to buy new cars all the time despite not really needing the financial help but she felt entitled to his contribution since he gave her a car for free that she felt wasn't good enough. Last time I saw dad he was quite rude towards me and I told my sister so too. She was all like oh you can button it saying that about dad and getting defensive over him. I told my other sister about it and she agrees if he's rude then I have every right to be annoyed by dad's rudeness. Our younger sister has told her why she doesn't see her much(because she purposely upsets her by telling her stuff about our dad when she doesn't want to know)and the drama queen dragged my name into her defense and slagging me off in the argument then messaged me saying if I'm gonna shit talk her to our younger sister then I can fuck off. Like what the hell she's the one who dragged my name into her defensive argument and slated me off rotten. She's only bothered because my younger sister actually told her to piss off slating me off so to be fair the statement she went and sent me can also apply to her. Would I be unreasonable to cut her off?