I am impressed with your decisions and your strength to see them through.
I know how gut wrenching it can be to practice detachment and tough love.
Your son had the typical reaction...to disappear. Often it is followed with anger
directed at us.
Denial + rationalization + procrastination are symptoms of his disease. My son would disappear and hold a grudge toward me whenever I followed through with
consequences. Sometimes he went long per. w/o contact. Part of the reason was
because my message stayed constant that being an alcoholic/drug addict was not okay.
Your son is young. My son is now 24. He too went to a short term rehab at 18 and another one at 20. He is now at a one yr. program where he has been for almost 9 mos.
It often takes a few treatments and some yrs. My son had to hit some consequences and learn that life as an addict wasn't working. He resisted going this time, but he did.
Until your son gets to this point, keep strong in your own al-anon program and satisfied that you are not enabling your son. It is tough as the parent of an addict.
Keep coming back here, there are lots of parents to share and offer support.
Try to have a fabulous life you deserve without letting the sadness overwhelm you.
It is possible, but takes support.