he's probably looking you up w/ any ace or better and maybe a queen because he's put so much in the pot. Have you ever seen him slow down on the turn and then do a blocker bet on the river? And when he improves how does he extract chips? Is he a checkraiser or will he lead into you and if he does is it a min bet? I think your fold equity here is pretty bad since there are no real draws present and after slowing down and then starting up on the river my first instinct tells me he has QJ.