Please advise re. multiple gastro problems

I'm hoping somebody can give me some guidance on my husband's condition(s). About 6 weeks after a car accident back in May, my husband (who was and has been extremely stressed over accident injury pain, being on disability with lower income and the possibility of losing his job over being on disability) began vomiting everything he ate and developed pain throughout the digestive system. He could eat nothing but Watermelon for about a month. Doc did endoscopy and colonoscopy and diagnosed him with esophagitis, reflux, gastritis, colitis, and hiatal hernia. The medications given to him caused severe migraines and didn't seem to help with the pain. Incidentally, they were also potentially carcinogenic. Anyway, we searched out a special diet, which helped to some degree for a while, but he developed an intolerance to it. We switched some things around, and he did okay on the second diet for awhile, but is now developing intolerance to it. Virtually anything he puts in his mouth causes his throat to constrict and causes him to feel like he's going to vomit. (I'm not talking about pizza or curry here, but the simplest of wholesome foods such as steamed vegetables or carrot juice or plain goat yogurt.) He started back to work 2 1/2 weeks ago because his boss recommended he get back to work as soon as possible, or they would have to hire somebody to fill his position. The stress of feeling sick and weak all the time while trying to work is wearing on him and increasing the pain. He can't focus at work and has nothing to offer physically - no energy. He's lost a lot of weight and I'm getting really scared for him.

What can you do when somebody can't swallow food or keep it down if by chance he's able to swallow it?