Hi, Scott.  Your son does sound like he's depressed, at least.  Is he seeing doctors at all?  Is it possible that he needs to be hospitalized?

Do you live in the U.S.?  If your son is disabled and unable to work, it may be possible to get his health care covered by your state or Medicare, but it takes documentation by a doctor and he might need a social worker to figure it all out.  I'm sure you're really worried about what will happen when he's off your insurance.  I have an adult son with a developmental disability and autism and he was on SSI and medical assistance for years, even when he had insurance coverage from my job.  He has a good job now himself and is still eligible for Medicare because he's considered disabled.  You could talk to someone in your county's human services department to find out what your options are.  If hospitalization would help, it would be good to do it now while he's still covered.

I don't know if this was much help, but let us know if you need any other information or ideas.  I know it's very frustrating when you have an adult child who's suffering because legally, there's just so much you can do.  I wish you all the best and hope you'll let us know what happens.