hello I would like to add one more suggestion .Smack or opiod  abuse usually needs a replacement therapy as it is very difficult to overcome. Many centres provide the buprenorphine  replacement therapy .This helps patients overcome the withdrawal and craving associated with snack abuse. Most patients on this treatment give up smack and go back to normal  life .please consult a psychiatrist to prescribe buprenorphine replacement therapy for your husband.

Recovery is a process and relapse is common in substance use disorders. Do not support the addictive behavior and at the same time do not take responsibility for the behaviour. Accept it as an illness and which will need intervention from outside. Motivation, addressing other concurrent psychological issues and medicines will help.