Obtaining power of attorney due to alcoholism?

My mother is an alcoholic and is steadily getting worse. It is killing her, both it and her smoking habits according to her doctor. I want to know if I can gain power of attorney without her permission as she is an alcoholic. I want power of attorney for 2 reasons. Number one, a relative is encouraging her and providing her with alcohol regularly and is the only reason she both chooses and can continue her destructive habits. I own her car and could easily prevent her buying alcohol is it were not for him and want to see about a restraining order. Also, she is slowly putting herself into financial jeopardy and will eventually not be able to pay her bills. I would like to control her retirement and social security and help her pay her bills and prevent her from taking out a 4th mortgage among other things. Can I do this? Would being an addict make someone not of sound mind?