So sorry about all these hoops you are made to jump through, Bluebell, between your son and trying to get him some treatment.
So, here's the "easiest" way to get them to rehab.
1. When there is a change in their behavior...agitation, sommulence, suicide threats, etc., call 911 and have them taken to the hospital. (now if they won't go, that's a negotiation and another story)
2. The social worker will be able to get him into a place that works with your insurance. It's way easier to get in straight from the hospital because all the documentation is there. The sequence is: Detox, psychiatric/drug treatment unit, rehab, sober living. You must maintain strong boundaries during all this, and not let them manipulate you into letting them back into your home.
3. They can just show up at a hospital that has a psychiatric/chemical dependency unit, say you're on xxx substance and that you want to detox. (May be the least likely scenario, although my son did do this. Maybe it would work if you gave him a choice between that, and the street).
Good luck with it all. 50,000? Who has that kind of money? Best to work with your insurance. Like the others have said, relapse is a part of the disease.