If your friend wants to wait 5+ years for treatment, tell him to file a claim.
He'll be off duty with 1/3rd pay, if the checks ever get sent out and after arguing it in court, if a court date is ever set.
At a minimum, and your state may vary, it'll be 60+ days before any sort of treatment. If it is something that needed treatment ASAP, he's SOL.
If his job decides to terminate him because of the claim, he has no recourse.
Absolutely nothing will give him his health back one he's signed up on the worker's comp treadmill of hell.
It is in the insurance company's best interest to keep paying their lawyers to hope the claimant goes away. It is in the lawyer's best interest to drag the case out forever. Don't worry if either the insurance adjuster or the lawyers get bored with the case, they won't settle, they'll just transfer it to a new person.
Plus, he'll have a black mark on his background check that says he's one of 'those' characters that files worker's comp claims. This will prevent job offers in the future.
If private health insurance or sweet-talking the doc's office gets the appropriate treatment, get it and avoid worker's comp.
Tell your friend to "STAY THE MEEEP AWAY FROM WORKERS COMP!!!!!!"
If you need me to, I'll come over and slap him silly 'til he decides against it.
Fly SAFE!
Jedi Nein