Great advice before me!
All I can tell you is that when I had had enough of my AD's lying, choas, and drama and it was negatively affecting me and the rest of my family and she was NOT caring one bit about the injury she was causing and was NOT trying to help herself; she was OUT!
It was the hardest thing I ever had to do but it was the best. It certainly saved us but she says, now that she is acting clean, that it saved her in the long run. She has even told me that giving her a safe, warm place to "crash", she never really did! And giving your son a warm and comfortable place to be will not make him want to ever "get out of the cold" - he will never HAVE to!
I know how difficult it is but you can take him to the Salvation Army or a shelter and tell him you love him, wish him luck and know that he has in him the strength to seek the help he needs.
But you and YOU along has to make the decision. YOU have to make a choice. You want him to choose to be clean and sober but you, too, have a choice to make as to what you will and will not tolerate. No, it's not easy but living with an active addict is not easy either. YOu have a choice to do so or NOT do so. and you have the right to that choice; it is YOUR home.
My AD has now told us that she was so glad that her dad and I set and stuck by a "standard" of behavior that we would accept. She said she knew she would have to set her sights to meeting that if she were to be able to come home and make it work for all of us.
If you "accept" less than you are willing to live with, then you send a message that it is "acceptable". And if it is not, then you need to take a stand; one way or the other but you can't have both. It doesn't work with an addict and you can't "bargain" for the acceptable behavior either.
Hugs,
Marteen