Help with a way to approach someone...

How do I tell her I don’t want to be her friend because she doesn’t know how to be a good friend and that it’s not ok what she put me through?

Here’s why : I have a friend who I take out with me everywhere I go. She eats, drinks and dances for free. When she drinks, she at times becomes violent but not always. She has acted up. She hit our driver while he was driving us home because he didn’t agree with her comment. She wanted to fight my friend and kicked him when he was dancing with her. (She thought he was trying to grope her. He’s a pro dancer.) I’ve told her I rather her stay at my place when we go out, because this way I know she’s safe and not picking fights on the street. That’s one issue. I think the only reason why she is my friend is because she dates my brother and because she knows I always have her covered when we go out. I’ve helped her out as best as I could. Whenever she needed someone to talk to, I was there and if she asked for something I’ve gotten it for her right away. Now, when I’ve asked her for anything, she would some times say she would do it and help, but most of the times it’s always talk. I asked her to do me a favor and she got what I asked but I didn’t get until 2 weeks after I asked her again. She then told me that she wished she had never agreed to do me the favor. My brother has told me that she doesn’t know how to be a friend. I’ve tried to talk to her but she says that she hates when I get that way. (When I talk about what’s wrong.) My brother told me that she says I overwhelm her when I talk to her and she doesn’t like the constructive criticism I give her. She even verbally attacked my brother when he made it clear that she dramatizes things and because she is an extremist. She assumes the worst of a situation before hearing about it. She says she doesn’t feel she should put too much into a friendship and doesn’t want to talk about something when things aren’t right. She recently put me into a very bad predicament. I took her out with a friend. She ran her mouth about things that had nothing to do with her. She ran into someone from her past. A photographer and she was excited. At the end of the night, she ran to him. Hugged him. She took a few pictures with him but wanted him to take pictures of me. After we said goodbye to him, she then tells me she didn’t want to run into him. Once she got home, she was drinking and she called me to tell me she didn’t want me to tell the photographer anything about her or her life. I thought to myself, I don’t know him or his contact info. He took my name and that was it to give me the pictures on FB. I never heard from him or got the pictures. My only form of getting in contact with him is through her. I told her we would discuss this when she was sober. I’ve been avoiding her since Sept 1st. I don’t now what to say to her. I’m very annoyed. What’s the best way to tell her that I really don’t want to be her friend anymore and that I think it’s wrong how she has been and that she is not a good friend?