I think asking that question avoids what might help you the most: acceptance
The relationship with your son is what it is right now. I would not speculate as to what the future will bring or what it might look like, either , because it causes you more suffering.
Just try to accept that nothing happens in God's world by mistake and that acceptance is the answer to all of my problems today. Hold your son in affirmative prayer (" thank you for keeping him save, for wrapping him in your love, for getting him the help he needs") and then turn it over. One day at a time .
