How To Reduce Depression?

My daughter, 38 years old, has a history of chronic pot use for roughly 25 years. Is also a periodic Alcoholic and has and my still be on ocasion taking an excess of Vicadine (semi-controled by her husband). I'm her 67 year old father, sober for 34 years via AA), I have tried to console my daughter on several ocasons concerning her drug issue's to no avail. She presently is and has been down to 95 lbs, skin and bones, loosing her hair, has had and continues to have anger and depression outbursts. Has been pulled over and searched by local cops because of the way she looks and her additude, even according to her. Currently she is haveing problems with anal boils, which according to a friend (former meth addict) is a common sign of prolonged/chronic meth use. I've approched her mother who she is close to, (we have been divorced for 25 years, but are friendly). However, her mother, as she was while I was drinking is in total denial as to the extent of my daughters drug use, as are other members of her family and friends. I do not want to alianate my daughter and family by confronting her, but am haveing a hard time just watchiing, and doing nothing, Any suggestions?

Thanks....Jerry