It's probably fair to say the good Dr. stand to receive a handsome compensation in a court, in the multiple of millions probably. United could, and probably will, try to dissuade him from taking them to court, and will thus have to come up with a sizeable offer indeed.
I have no doubt the lawyers of UA will make it clear to the beancounters of same, that offering an obscene amount of money will, in the long run, be the cheaper option.
What I'm hoping for however, is that a 69-year old doctor will be satisfied with whatever a court will award him, even if it's likely to be lower than what UA offers out of court.
In which case there's nothing UA can do, but brace itself for a round of court proceedings that's likely to cause lots of headlines all around the world, with the possibility of repercussions which may have a lasting, and positive, effect on the way airlines treat its passengers.