600 buy in Borgata tourn: please coment on hand

My friend was in the following situation. I told him he misplayed this hand. Please coment
Friend 6000 chips
opp: 6500 chips
Blinds 100/200 no ante yet (blinds 1 hour long)
Friend: 5 position KdQs, folds to him, he raises to 500 gets 1 caller on the button. So it's heads up at a 9 person table.

Pot is 1300$
Flop: QcQh2h

Friend: leads out for only 600$
opp apparently (so my friend says) thinks about it for a while reraises for 3000
Friend: pushes ALL-IN
opp: Calls with AhJh

Turn was a Heart and my friend got busted out!!
My problem with the way he played the hand after the flop was his weak bet. with the 2 hearts on the board why would you give your opponent an opportunity to improve for cheap.
I would have made a much larger initial bet after the flop. I think my friend gave the hand away which let his opp get so pot commited that he had to call my friends all in move. I think if my friend came out betting more aggressively that he would have taken the small pot down and lived to see another hand

I don't get it.

He got his money in ahead with the best hand and opp suckedout on him. I dont think he's folding the nutflush draw to any size bet, other than maybe an overpush all in. Even in that case he might think its complete air and call.

I'm not really sure how you can advocate playing this hand in a way that would FOLD a worse hand. ..instead of getting the worse hand to go allin? I think its somewhat too results oriented.

i dont know where to start

im gonna say dont post in hsnl unless u have reads/history/things which would makes us think about the hand in a way which doesnt just involve fundamentals