The best and most convincing way to convince someone to accept help for their addiction towards drugs is to stage an intervention. This intervention can be in two ways. First being direct intervention, in which the people who are dearest to the addict i.e., his family and friends write out their difficulties and grievances faced by them because of the individual's addiction.
It's an obvious thing that people who are close to the addict will feel that the drug which is so harmful to him has become more important to the individual than his family and friends. By making him realize this, they can convince him to accept aid for his drug addiction. This means to intervene is often recommended by Drug Rehab facilities in the United States.
The second form of intervention is an indirect intervention which can be by convincing people with a drug addiction issue to accept help. The drug rehab counselors work with the individuals who are a part of the life of a drug addict rather than working with the addict himself. This can be a helpful way of eliminating rude behavior or unhealthy love from the family and friends towards the addict.