How do I deal with my husband being in rehab?

He is in a Christian rehab for cocaine abuse. I have asked similiar questions before, but I want to get a lot of opinions. I want to know how to help support him now and when he returns home in November. Please help me.
We also have a 2 year old son. I get to go see him this Saturday and I wanted to get some pointers as to what to say to my husband.
I never have and never will do any kinds of drug.