Bonterwin, my adult son is an addict also and your story could be my own. For too many years I tried everything I could to help, to stop the insanity, and it just never came out well for me or for my son. He has now been missing for more than 10 years. I didn't fail as a mother, he made some bad choices and is living with the consequences.
What helps me get through my days is to say a prayer every morning asking God to take care of my son and then living my day in faith that He will and that He can do for my son what I cannot.
Hugs