[wheatrich]

I'd probably raise fourth and probably play the rest the same way--he's either got queens up or he's got you beat on sixth. Depends on how sure you are he's got that hand. Sounds like you're answering your own question though. I probably don't reraise sixth just because of the possibility he's got something like Ah 2h Qh and just backdoored the wheel/low (unless I'm pretty sure it's Q's up of course).

edit--I'd probably reraise third even to try to get it HU with the Q as the K's in the hole are well disguised given that I'd do that with other 2 type hands.