Which is the real him? on or off the drugs?
Actually, the problem is neither one of them are the real him. He's an addict. His brain is messed up. It takes more than 3 weeks to recover from drug addiction and become a whole person again. It takes months and months and sometimes years of REAL RECOVERY. And in my experience, you don't go back to being the person you were before you started using drugs. You become a completely new person. One who never would have used the drugs in the first place.
I think that it is important to focus on the behavior that you will and will not accept in your life. Set boundaries for how you will allow people to treat you. Write them down. Write down the steps you will take if someone violates your boundaries. And most important, follow through.
Example of a boundary:
People will treat me with respect in my house or they will have to leave.