LMM, I'm so sorry to hear what you are going through. I had a son who was addicted to heroin, so I can complete relate to your feelings of helplessness, frustration, guilt, and fear. SR has a forum especially for friends and family of alcoholics. You will find people there who are in your shoes and know exactly what you are going through. You should check it out:
Friends and Family of Alcoholics - SoberRecovery : Alcoholism Drug Addiction Help and Information