The short answer.....no.
As the codependent (see my post above) I did very similar things that your mother is doing (although I never called my dear darter names, I did use manipulative tactics like Guilt and Manipulation) to keep her in the dance of addiction. This is why they call it a family disease.
Take care of you. Take care of your child. And don't fall for the manipulative tactics of your mother or your brother.....they are both addicts in a way......just on different ends of the scale.
Welcome to SR.....I hope you find support here that helps you deal with the addict(s) in your life.
gentle hugs
ke