Missed nut-flush-draw on the river deep 1/2NL

[Cryptorchild]

Full-ring $1/$2 NL

The utg opens for $6. He's very bad with stats something like 45/9/1
He gets cold called by villian utg+3 who is 10/4/3
I call from the button with K[img]/images/graemlins/spade.gif[/img]J[img]/images/graemlins/spade.gif[/img] and we see the flop 3-handed and we all have over slightly 200bbs.
The flop is A[img]/images/graemlins/spade.gif[/img]6[img]/images/graemlins/spade.gif[/img]2x. The preflop raiser checks, and villian bets $10 into $20. I call, the other guy folds. I think his range is fairly wide here. Being set of 2s, 6s, flush draw, pair of aces. I think he'd reraise AK, and is too tight to call preflop with very many bad aces, although he might because of the preflop raisers stats.

The turn pairs the 6 and he bets $20 into $40. I call.
The river pairs the 2 missing the flush. And he bets $40 into $80.

Now, what hand here makes sense? If he thinks I have spades, shouldn't he check to get a bet from me? Unless he himself has missed spades as well. If he has aces what does he expect me to call all three bets with and win? AQ vs. AJ? I felt like it was quads or spades. I thought for a while and considered calling with K-high to catch missed spades. And then also thought of raising because I feel that would be a tough call for aces. But in the end I chickened out and folded.

What do you guys think of his line? And what do you put him on?

[Cernunnos]

i put him on an A at least possibly AA, and i think that given your action up to know, unless he has seen you slowplay monsters, he is gonna call on the river,

You have already said he is bad, so your giving him to much credit by saying shouldn't he check the river to induce a bluff.