I went through something similar in '97. I was self-employed and managed to get bogus insurance for the self-employed. I had to have emergency surgery and the insurance company denied ALL of the claim because "being female is a pre-existing condition" (I had a tubal pregnancy). It ended up being over $10,000, and then they started laying on the finance charges and interest. I finally got it all paid off about 2 years ago. I'd always been told that medical bills are not considered 'strikes' on your credit, but let me tell you that they are.
Once he recovers, he'll need to keep all the bills very organized, as each department in the hospital will bill seperately and it will get very confusing as to exactly how much he owes and to whom. I used one of those big accordion files; one pocket for surgical, one for lab, one for the anesthesiologist, one for each physician, etc. Looking back, I wish that I had gotten a consolidation loan after the invoices were closed so I could just make one simple payment each month and hold down the finance charges. I tried to take care of all the seperate bills on my own and it was really confusing and stressful. I ended up with judgements against me, which was good, as it stopped the finance charges and consolodated all the different bills. Hopefully he'll be back on his feet soon and able to find a job so he can start picking away at it. It seems impossible at first, but eventually he can get it all paid down.
Hoping for a speedy recovery for your son.