That's not that unusual a tactic. He's going to continue doing it till he gets caught a couple of times. In freerolls
he may continue regardless of how much he loses. You have basically two options: 1. wait till you or he gets moved to another table, or 2. wait till you get a good hand, then go for it. Accept the fact that when a player does this it becomes a free-for-all, meaning he's going to win sometimes with 72o vs AA. That said the regular odds
haven't changed - QKs is still going to win more often than J3o. Unfortunately if he's deep, he's got the chip advantage, and depending on the differential, can easily outlast you.