@scooterbill, Advice - I have none, but here are some thoughts.
My first is a question: Is his doctor following his health situation, or has he shared what is going on? Since he if feeling so poorly, he might need someone to contact the doctor. A doctor can only act of he/she knows what is happening. Your son's current nausea. not eating, sleeping, and general downward curve are indications that his doctor should be kept informed.

Does your son have insurance that would cover him in a non VA setting? If he does, that could be a resource to tap into. There should be a patient rep or ombudsman at the his VA, Has his wife spoken to them for resources?

Scooterbill, Your son needs nutrition. When I had nausea my GI suggested tat I try Ensure or similar nutritional drink. Yes, I had a gag response, but drinking it cold with a scoop of ice cream helped me to get it down.