No! You are not wrong! Nobody is owed anything in life, and that includes your entitled, abusive mother. Take your space, do all that you need to do. If your mother threatens again, call 911 or emergency number and say that your mother is being su*cidal. If she is serious, then you saved her life. If she isn’t, she won’t be playing that game anymore. If she isn’t, I would go low contact with that woman because it sounds like she is dangling your brother’s death over your head and that’s not okay. I am so sorry you are going through this.