$40/$80 big blind special

[scags23]

In thhe shorthanded games I play on mainly online, when someone has a 2 over flush draw they wait to raise turn with their draw as a strong semi-bluff. The flop 3bet is such a weak play these days, it seems people wait for the time to represent a real hand. Thats why I thought he played it like a flush.
The player was described as being a tough player, and he regarded the hero as ABC player. Therefore, the ABC player 3bet the turn and bet river with a flush on board and 4 cards to a straight. Therefore, I think river 3bet is bad raise