Drama from my momma

Hi all! I need everyone’s opinions. Backstory. My mom and I have been pretty close. I have 2 sisters and a brother. My mom definitely favors my little sister. Who no one has the best relationship with because she’s stolen from all of us. Not just little things, but hundreds of dollars. She decided to take her to Vegas (she’s 16) and didn’t invite anyone else. She asked me if my brother was hurt by that and I told her he might have been and she should talk to him. She immediately got defensive and got very upset. My little sister was in the room when it happened, she looked at her and said you have always hated her. Which isn’t true. She isn’t my favorite person but we were actually getting closer. She ended up calling me and just dropping it two weeks ago. Then today she brings it all back up saying it’s my fault my brother won’t call her. He doesn’t talk to her because she is so negative and gives him anxiety. So it ended with her telling me to get off my high horse. Then she texts me all of this. I am so beyond upset because I know she is lying. I know I never said those things because I have never thought them. I am just at a loss. I’ve been working so hard to better myself and be a positive happy person (I have anxiety) and she is just so negative. During our talk she called me stupid for thinking that it wasn’t normal for parents to favor one kid. She has called my older sister pathetic. She is just toxic. Any advice is appreciated so much.