I put him on
![The Ace of Spades [As]](https://pofex.com/images/smilies/As.gif)
[8s] or
![The Ace of Spades [As]](https://pofex.com/images/smilies/As.gif)
[7s]. with an outside chance at 77, 88, or TT
when a bad player flops a set and bets small, if they're raised, 9 times out of 10 they'll reraise. same thing for the turn, if in fact he flopped a set, when you reraised him he would have pushed.
He bet the turn when the bottom card paired, and he bet tiny, then called you raise leaving him with $210. if in fact he had a made boat at this point there's no way he doesn't at least min raise you
Still, if you bet the river you might as well push. if you do, the only hands i can see calling you are A5,
![The Ace of Spades [As]](https://pofex.com/images/smilies/As.gif)
[Qs], and a boat. maybe TT, but like you said, that should have folded earlier.
Long story short, i don't think the range of possible hands that he will call you with warrants the risk of losing to the boat. I vote for checking behind him and finding out what he's playing like this.