My "awakening" came after I called a drug program for help. My son had come home so sick and filthy that I had him strip at the door, put his clothes in a garbage bag, and head straight for the bathroom shower. He took "stuff" out of his pockets and I confiscated it and hid it. Next day, clean with fresh clothes and a full stomach he left (with most of my cash and some jewelry he had stolen). The first advice I received was "Give him back the drugs. His supplier will kill him and you if you don't".
Jim is right. "Sink or swim" means he may sink. But if his swimming means dragging you under with him and a refusal to learn to swim...
My son had survival skills. He abused many people after I threw him out. Eventually, after one too many beatings, he wasn't pretty enough or handsome enough to find another enabler.
I would not wish this experience on my worst enemy. And obviously there is much more to the story. But if your child is addicted, you can do nothing but back off and let him go his way.