[gulebjorn]

What is he calling the flop and turn with? Seems a little strange if he was drawing to a backdoor flush all the time. Was the diamond on the flop the ace? Ax of diamonds is the only hand i see that would be sticking around for the flush. Maybe KQd or QJd, but that's a long shot.

I'd say bet the river. If he's been tricky and trying to push people around with his big stack, i'd even call a c/r if it's not too big.

Did the other two fold on the flop?

Edit: got distracted while posting this and noticed this has been posted and answered by TWP and OP while i was away, so feel free to ignore