2 things assuming you too are playing solid poker.

First, don't change your patterns. When you catch that big hand or hit a good flop trap him. If he likes to steal the pots you are involved in he is set up for a trap when you have a monster or hit a big flop. Also, you may consider that some of those laydowns are good because you are beat but you are still in the game.

Second, play some poker. Once in a while you have to put him in his place and come over the top of him even when you have nothing, or even the smallest piece of the flop.

When you are down to 4 players in a game, the cards don't matter too much.