T5o huhu unraised bottom pair, bet turn?

bet fold the turn. If we get to the river what is he calling with that we beat? Will he bluff the river with a busted flush draw?

check flop

I would play the same on the flop (we have a pair so it makes sense to bet in order to verify if our opponent is connected to the board) and then ckeck the turn against this guy. If he bets then fold. I see no reason to invest any more on such a turn. With flush draws he will call (sometimes even raise) and then OTR it will be an unpleasant situation most of the times.

Long time no see taavi.

I'm not sure what the last two statistics are that you list. I wonder what sort of hands he has been limping with pre, does he raise Ax pre? It seems crazy to check fold a monster like this on the turn, but if he doesn't limp his aces pre, then there doesn't seem enough hands that he peels on the flop that we beat. I'm thinking he has JT, and worse 5x, but everything else got there. In other words, if he is raising all his Ax pre, we are in bad shape. If he still has Ax in his range he likely checks it back on the turn anyway.

In short, check/fold turn