Hi,
I agree at the age of about 18 they feel indestructable, i remember my son at that age never even smoked let alone did drugs and then i guess he decided to just go out one day and try everything under the sun that he could possibly get his hands on, there were never enough parties,never enough "friends", drinks, pot...the list goes on, he was always in control, he new it all, anything and everything i said and did fell on deaf ears and me and my husband watched him slowly dig himself into the hole that he is in now and let me tell you his addiction has taught him something no one else could have , he is a slave to it, never thought it could happen to him . I also agree that it would be easier for me to let go of him if he were not living with me , although i have changed alot i still am an enabler . I dont know what advice to give you except do what you can live with i think we have to try in order to learn . good luck