Vaya, your son will need to want recovery for himself and I pray that time comes soon. Long term inpatient may be his best bet but any program will only be as successful as his willingness to work it.
I had to let go of trying to save my son from himself, trying to save him was killing me.
So I pray and ask God to do what I cannot and then live my life knowing it is truly out of my hands.
I will pray for your son too. And for you because I truly know your pain.