What To Do?

Dear IL's,
I am sure many of us are sailing in the same boat. Parents who expect us to behave the same way they want us to. Say good about people they like, say foul about those they don't. Become puppets. Don't ever dare to even voice our opinion. If at all we do, then crying and emotional blackmailing. They can hurt us in whatever way they want. But we are not supposed to react or keep quiet. If you do, you have to hear stories of how much they struggled for you and at the end of the day, you turned hostile and are selfish/ useless children.

I say these in wake of my experiences. My mother has some issues with my father's sister due to some unprecented events which happened in recent past. She has vowed not to go to meet her even if she dies. She doesn't leave any chance to foul mouth her. And also expects me to join her in doing so. Personally I love my bua since things were not so had from begining. Ever since my grandmother passed away, she has been a granny figure to us. But now things turned so and situations turned overnight. My father favours his sister. This makes her all the more angry. And so she keeps on foul mouthing both my father and his sister. I don't like it somehow and if I say something in my bua's favour, then gone. She becomes a cry baby and I too becomes bad for her. My sister is always mummas girl. Whatever my mother says, she blindly follows. This has spoiled the whole environment of our house. My mom and dad fight often on the issue. Then I get phone calls from both blaming and Ill mouthing each other. I get stuck in dilemma. But I have observed a change in her behavioral pattern if it concerns her family members( maternal house members). Whatever they say, gulp it down the throat without saying a word. If we say or react, then whole drama unfolds. In short, my father favours his side of family and my mother hers. In all this our family of 4 suffers.

Now my mom is here with me. Today morning she was reminiscing old things and foul mouthing my bua. I didn't say anything..Kept quiet. Then she created a big issue. She said I was very self centred and selfish. She said I have a very bad attitude problem and I just want her for name sake. That I don't care for her and that I am a bad example of how a daughter should not be. From morning onwards this has been going on and I said sorry so many times ( I know I am not wrong but still to stop hearing these cuss words ) but she has not been talking to me. I don't know what to do
I am feeling suffocated in all this.

Any suggestions what do I do? Do I change for her, act for her, maintain silence or maintain my stand. I am not comfortable changing my stand because I know I am not wrong. It may sound as my attitude but in front of my conscience I am not wrong.