I feel alone

I have a brother with bipolar disorder, she doesn’t want to take any meds or go to therapy. The last therapist she had found other disorders but he doesn’t believe them and just stopped going.

I’m scare because idk how he will react sometimes. I realized that sometimes when he is good and acts sweet towards me it’s because he wants something from me, like a favor or other stuff. He switches often, when she is mad she takes it out on me, not like she used to but verbally it’s horrible, she says mean things to me and criticize me, even if I didn’t do anything to her.

I don’t want to make him mad because I’m afraid she will ruin my life. There are a lot of things that happen to me with him that I can’t tell. I want to scape him but I don’t want to leave him alone because he is my sister and she is struggling with things. But do I really need to accept this treatment? I’ve tried to talk it out with him, he doesn’t listen, he says that what I tell him is made up or that I have mistaken his behavior, or that I’m just manipulating or that I don’t understand. When he does listen, he talks about others when I’m talking about us not them, he promises that he won’t do it again but he does it anyways.

it’s a cycle and I don’t know how to handle it. I feel lonely I don’t have anyone to talk to, I’m just 14 I don’t what to be in this situation.

im tired of justifying or defending that behavior. I can’t keep this up. I need help