I am playing 2-5 PLO with mandatory $10 straddle. Table is very loose with 2-3 good players. The rest just enjoy gambling and seemingly losing.

Villian (good thinking player) opens to 35 in middle position and gets two calls I 3-bet on the button to 135, all 3 call.

I have AcKsQhJd and started the hand with roughly 8K. Villain covers. We are both big winner in the game.

Flop (~550): KhJc5h

All 3 check to me and I bet 300
Villian raises to 1000
Other two fold, action is on me?

Three things.

1. Villain has a strong hand here. His range, in order of likelihood, consists of flush draw with AQT, KJ with a flush draw, KQJT, KK, AA with nut flush draw, some other gutter nut flush draw pair combos, JJ and maybe AhQTx with no flush draw.

2. If we call villain is betting ~2k on all blank turns. He is also the type of player that would at least consider betting pot on the river if he had a draw hand that missed. Other than that he will bet flush or straight cards mostly only if it makes his hand and bet a king or a jack only if he makes full. Not sure what he does if the 5 pairs.

3. Taking this line he is almost never folding on the flop.

What is the best course of action and why?