Is a call here just dumb?

[CryptoManiac]

SB is 44/15/2.5. I have played with him a lot before and he isn't as loose as his stats suggest. He also knows I CB a lot.

Who calls on the river and who folds? What do you think of the turn check?

What about his betting range on the river compared to my calling range...does a call explain why I'm losing so bad at the moement?

Seat 1: CO ($190.72 in chips)
Seat 2: BTN ($34.50 in chips)
Seat 3: SB ($97.25 in chips)
Seat 4: BB ($125 in chips)
Seat 5: UTG ($42.28 in chips)
Seat 6: UTG+1 ($154.40 in chips)
SB: posts small blind $0.50
BB: posts big blind $1
----- HOLE CARDS -----
dealt to CO [K[img]/images/graemlins/heart.gif[/img] K[img]/images/graemlins/club.gif[/img]]
UTG: calls $1
UTG+1: calls $1
CO: raises to $5.50
BTN: folds
SB: calls $5
BB: folds
UTG: folds
UTG+1: calls $4.50
----- FLOP ----- [6[img]/images/graemlins/diamond.gif[/img] J[img]/images/graemlins/heart.gif[/img] T[img]/images/graemlins/diamond.gif[/img]]
SB: checks
UTG+1: checks
CO: bets $15
SB: calls $15
UTG+1: folds
----- TURN ----- [6[img]/images/graemlins/diamond.gif[/img] J[img]/images/graemlins/heart.gif[/img] T[img]/images/graemlins/diamond.gif[/img]][K [img]/images/graemlins/diamond.gif[/img]]
SB: checks
CO: checks
----- RIVER ----- [6[img]/images/graemlins/diamond.gif[/img] J[img]/images/graemlins/heart.gif[/img] T[img]/images/graemlins/diamond.gif[/img] K[img]/images/graemlins/diamond.gif[/img]][5[img]/images/graemlins/diamond.gif[/img]]
SB: bets $48.50
CO: ?????