I have an addict Ex husband and I am going thru what you are going thru. This weekend I found out that I can not control him or his actions, my x has been in and out of jail, prison once since he was 18 and he is going to be 45 this month. He was recovering in a State runned house. He has been in rehab 8 different times for Meth. He can only stay clean for a very short time. He is looking at possible a 10 yr stratch this time. He is still out on the streets but the warrents will start coming because he is using again. Do not worry about your son,he will be fine. Until he hits is bottom he will never change. Who knows he might not want to change, everyone is different.
What are going to do for you and getting the help you need to heal yourself. It has taken me 18 years to finially start getting the help I needed to start healing me. Do not wait that long.