there wasnt much you could do, from looking at how the hand was played out it seems like he didnt know he made his flush. I mean what would be the point of drawing to a flush and then when you hit not raise? Especially since you where betting into him the whole way, screwy play on his part in my opinion. There wasnt much else you could do, I mean he called a small preflop raise then luckly for him he caught a flush draw=9 outs, then on the turn he hit a double gut shot=8-(the two D's for his flush)+9=15outs on the turn. I donno what else you could have done, raise harder preflop and nail him on the flop, even though it was incorrect for him to call on the flop.