Use regular reminders of personal motivations like family, career, and health.
Or
Keep his schedule and friends as consistent as possible to avoid too many changes
I was once a drug addict, and both of these things helped. Keeping a tight schedule and sticking to it really helps, especially in the beginning. And Using regular reminders of what you will lose/ and what you want for your future are both ways that really helped me.
Gravity is an attractive force that INCREASES as the mass of an object increases. An object with greater mass has a larger gravitational pull than an object of a smaller mass.