My son relapsed quickly after his 1st two inpatient rehabs.
Last yr. he was close to death at age 24 and went to an 18 mo program.
This time he had lost enough to see that his life was unmanageable.
You might need to detach for awhile, til your son is really ready to work a recovery program...even tho it is sad to watch him like this.
Do you work a program through al-anon?
Don't give up...be patient and learn ways not to obsess.