I asked sis about her hate for stepmom and she said that she thinks stepmom is a "annoying bi*ch", "stupid and irritating", blabla. She thinks stepmom changed dad. She did. But in a good way. He's happier, often in a good mood, he is more positive.. I think she's really good for him and I like him as he is now. He's happy and it feels better to be around him than if he's not,ofc.
But, sis thinks that's not the only change. She thinks stepmom is changing him completely as a person and she doesn't like it. I asked her to tell me specificaly what did change about him, but she says it's general, nothing in specific. Which kind of makes me think that it's not really true that he changed as a person, but just that she feels differently about him. Which makes me feel uncomfortable since I know dad loves us and loves spending time with us, and I don't want my sister to stop loving him or something. I don't know if that's possible but if it is.. I don't want that to happen.
So when I told her that stepmom is not bad for dad and he's not worse, she got angry at me saying I'm "on their side", which is not true. I don't want to be on anyone's side because I don't think there should be any sides at all.
But still, she just hates stepmom and says she "want the bitch to go to hell..or at least as far from me as possible".

I told mom,she talked to sister but nothing. Mom talked to her, i was present for the most part. She first talked to her about how sis feels, told her tht it is normal that dad has a woman in his life,that sis wouldn't want dad to control her love life in the future, and even asked her about stepdad. But sis said she likes stepdad, but hates stepmom. So mom told her she doesn't have to like her but she needs to act kindly because stepmom deserved it,but sis said "no fucking way I'll be kind to that b*tch"
So mom told her no laptop or tv tonight or tomorrow morning and she must stay in her room for the rest of the evening (sister and i usually sit in the living room and do something together in the evening) because she shouldn't call stepmom names and warned her about future consequences if she does it again.

But when I went to sister's room and talked to her she kept calling stepmom names..Which I really don't like to hear as I don't mind stepmom but ok.

We are supposed to go visit dad tomorrow since tomorrow is a holiday to us, but sis refuses and says "no fucking way in hell i'm going there".

And I don't know what to do, can I even do anything. :?

It' surprising for me to see my sister be like this as she was never rude or bitchy to anyone, this now is actually quite shocking for me. If anyone, i was always the "trouble" - I wasn't really bad like some of the stepkids here or bad in general, but sis always watched out for the rules, and I'd break them - pretty often in one time period. I stopped that but yeah..I still do it sometimes while sis NEVER. So this now is..um WTH for me.