Just one problem... You say he's a nut camper, and very tight - yet you're giving him credit for the nut flush? That would mean that he is NOT a very tight player, because if he has the nut flush then that means he called a preflop raise with with AT or less from the small blind... which contradicts your read/his stats. Not to mention the flop call, which is uncharacteristic of a tight player, who won't call a pot sized bet with only a flush draw.

Methinks he got Kings Up or a set on the river... and didn't put you on a semibluff/hearts draw. I'm never laying this down, even with villain's numbers. In fact, the fact that he plays so passively makes it more possible that he wouldn't raise such a hand.