What do i do if my sister have a drug problem?

Your sister has to: recognize that she has a problem and she has to want to do something about it. Families often feel helpless, hopeless, angry, ashamed and guilty, in various combinations. Concerned family members can present their worries to her, trying to help her see the problem, but this often results in denial and anger on her part. Attend Alanon meetings for your own sake, not hers, it may help with enabling.