Tough spot wit KQ

[Gorgi24]

I really have no read on villian as he has just played a couple of hands and he doubled up on a set over set..

0.50-1 NL. 6 handed

UTG ($88.25)
MP ($70.80)
Hero ($142.55)
Button ($82.32)
SB ($160.25)
BB ($97.80)

Preflop: Hero is button with Qc, Ks.
2 folds, Hero raise to 4.00, Button folds, SB calls, BB folds.
Flop: ($9.00) Qs, 6d, 4s (2 players)
SB checks, Hero bets 6.00, SB raises 6.00 to 12.00, Hero calls 6.00 <font color="blue"> Min raise??? is this screaming strenght? </font>

Turn: ($33.00) 2d
SB bets 20.00, Hero calls 20.00 <font color="blue"> I'm totally lost here, is the call fine?? Should I just fold the hand right here? </font>

River: ($73.00 ) 4d

SB bets: 50.00, Hero ????

I could only think of 2 hands that beat me 66 or AQ. What is his range? Can I call this profitably??

Comments on all streets are appreciated...