Yes. Addiction effects the whole family. That's why to best recover the whole family usually needs help. Are the consequences getting any better by avoiding them now? Seek support, try alanon. Codependent and enableing behavior are very common but they dont make the problem go away, they usually make it worse.
Yes. It's been called codependency. I can recommend an excellent book called: codependency no more by melody beattie. It is really a must read for someone in your situation. Good luck.