Maybe this is far-fetched, but could this individual be looking for a meal ticket?
There are people out there who are professional Complaintants. IOW, they sue a lot. Not to say he is necessarily, but some folks look for an opportunity to exploit. Was he THAT tired, that the whole "back to gate" PA and deboarding process was oblivious to him? Not for nothing, but I'm usually pretty alert even when dozing off in public places. The slightest inconsistency in noise or movement will wake me. Not only that, but how can you comfortably engage in R.E.M. sleep in an RJ seat with the PA's blaring to the point of not being aware of a gate return with all of the other passengers shuffling about. Just sounds kinda weird.