We know he's seeing a lot of flops. We should assume he's not folding any piece of the flop, that he'll be calling gutshots, and that he'll probably even call ace high. Too often we're getting called on flop and we're on the turn in a bloated pot with seven high against a fish with half his stack left. That is not value.

If we know he's folding a lot on flop, then ok I can accept the ISO. Otherwise, fold or limp.