[NLfool]

on a flop of J27 the guy either has a set or a flush draw. He played it well. The kid isn't going to call a huge bet on the turn paired board with a 5 high flush draw, he will however call or bust Mike with a set. So he checks it to induce a bluff on river. He has to have some doubt as to whether the guy had the set and now a boat, why else call with trips A kicker.

This isn't online poker the kid isn't a total donk. Sure MM's hand is monster on the turn but if he bets big he isn't getting that call from a flush draw on a paired board.