Look at his behavior, is he bored, does he wanna go home? Than he won't care about his money any more . It's also possible he's on tilt, has he lost lots of hands lately and had many suck-outs? But this situation is the most unlikely.
It's more likely that he loosened up and called with a 10 4 or 4 8 and hit his miracle flop (2 pair). He tought you would call because you wouldn't be able to put him on this hand. That's why i think he tried to trap you. Online they do it all the time, maybe that's where he learned it from.
Another scenario:he had pocket jacks or AT (top pair, top kicker) and he knew that if you had higher pocket pair you would have bet more then 2$ so he's quite confident he has the best hand (an overpair) but he doesnt want any Q,K,A to appear on the turn or river. He's scared, because he had suck-outs like this before with this hand, when he tried to slow play it. And he knew, because you bet preflop and after the flop there was a raise and reraise he knew it wouldn't be easy to make you guys(=the people that raised= the ones that made a pair 10s with the board or the ones with 2 overcards, which aren't always the best hand when you get to the river) fold  |