Detachment is about living our own life, and allowing your loved one to live theirs. It is about recognizing our powerlessness over their addiction.
Don't allow your loved one to depend on you. Don't allow yourself to enable him or her. Help him or her to stand on his or her own two feet. It's the only way. If you are some how dependent on him, you need to change that. Addicts are just not dependable.
With our 21 yo son, who is actively using marijuana, we found it impossible for him to live at home and detach. He was not serious about recovery (or for that matter anything else). Finally we asked him to leave. He is still active, but surviving and learning how to live. We still love him, and worry about him, but from afar. If and when he is ready to recover, we will help him if we can.