Hi Dawn. I'm sorry that you had to find your way here through addiction but this is a great place to be with a lot of support and resources.
Have you taken him to the ER? In my experience though they have to be in full blown withdrawal to go through a detox and can then be admitted. Then at least you will have a history of medical intervention. Can I ask what drugs he is using?
Some insurance companies require the person to to have tried "x" amount of outpatient programs before they will cover an inpatient program. It's ridiculous honestly.
I'm a mom of 2 addicts. One smokes pot and pops pills and the other progressed to IV heroin, went to jail and is now facing 3 yrs probation. It's a very rough road to have to walk down as a parent. You are doing the right thing by trying to get him help so early. Don't give up. The squeaky wheel gets the oil in my experience.