UA have the eyes of the world on them right now.
The quibbling about T&Cs, captain's discretion etc. is, for them, like arguing what piece the band should play whilst the ship goes down.
If, whilst at the top of the news cycle, they were to publicly and unconditionally offer this guy $1,000,000 by way of apology/compensation it would *pragmatically* be money very well spent. They'd likely get it back in stock value before they had time to sit down.
(BTW, please no blah about setting 'precedent' unless you are a lawyer: the worst precedent to set is avoiding doing something smart for fear that someone might demand you do something stupid later on on the basis of bad analogy).