Is it normal mum takes her side

Apparently shutting the door when my sister is in her room is rude lmao?
I say well at least I'm not slamming it or raging at herike I used to. Shes like yeah that's what childen do, childish. I say yep you're right it was childish but now I dont do that anymore and I simply close the door yet she says its shutting her out and she doesnt like it lol!!! I say idc about her fucking feelings !!! You know why I do that. Shes like so you're gonna hate your sister forever? I said unless she changes or comes to me. She said hows she gotta change? By not having a brand wanting to ditch the family business? I say how come your not mad at her for ditching the fam business she's only 21 and ditching amd here I am 26 and havent ditched!! Wow
I said what about her best mate Jason?? I spoke to him and he blocked her due to her walking on him. Shes like domt bring him up and dont talk to him as it's her ex friend. I said I will bring him up! He has feelings too and I am on his side. She doesn't want me to bring his name up because I am RIGHT? That's it aye?? Why else turn a blind eye and say nothing in relation to him. In fact she used to adore Jason as a good friend and now she acts fuking indifferent. Doesn't even talk to my sister about any of her wrong doings.
Shes hypocritical, and self absorbed! Mother is a cunt and takes her side!
Sister runs over to her bf place 24/7 like a bitchslave trying to fit into hetronormative society. She went on thurs to Sunday, got up at 6am to then drive 20 mins back home to then go to work at 8am to 5pm. AND THEN run back over to his on Sunday evening to stay the night when she has work again Monday!! She also works in the family business lawns and gardens. It's a physically demanding job, she also gets anxiety at his. She looks malnourished and skinnier yet doesn't dump him or stop over working. Psycho