4:1 on river, & his hand is an open book? Fold?

Hold'em NL ($0.25/$0.50)
Seat 6 is the button.
Seat 1: Crunsch ($48.35 in chips)
Seat 2: bam19 ($92.10 in chips)
Seat 3: bezzan ($30.45 in chips)
Seat 4: nlwjjb ($38.85 in chips)
Seat 5: Duffy010 ($26.85 in chips)
Seat 6: HERO ($63 in chips)
Crunsch: posts small blind $0.25
bam19: posts big blind $0.50
----- HOLE CARDS -----
dealt to HERO Q:heart:: A:spade:
nlwjjb: calls $0.50
Duffy010: calls $0.50
HERO: raises to $3
Crunsch: calls $2.75
bam19: folds
nlwjjb: calls $2.50
Duffy010: folds
----- FLOP ----- 5:spade: 8:spade: 7:spade:
Crunsch: bets $7
nlwjjb: folds
HERO: calls $7
----- TURN ----- T:spade:
Crunsch: checks
HERO: bets $19.50
Crunsch: calls $19.50
----- RIVER ----- 5:club:
Crunsch: bets $18.85 and is all-in
HERO: calls $18.85

Do I need the discipline to fold this or is lower flush + bluff enough reason to call?

Fold getting 3:1 with top flush b/c you're afraid of boats? Erm, no.

Edit: pardon, 4:1. Make that, "hell nah."

What can you put opponent on other than a boat? He open pushes the river when he check/called the turn.

Ksx, Qsx, Jsx. If I'm a typical shitty donk with, say, KsQd, I'd probably play the hand this way. Bet the flop with draw, get called. Sneakily check the turn when I make my hand b/c slowplay is teh shit. Push the river. I think lower flush draws + bluffs + weird inexplicable shit like AA or something make this a no-brainer call getting 4:1.

hmm, I have a hard time laying this down getting 4-1 against an unknown.