Villain is 36/18/13 over 78 hands. Several hands ago I saw him double barrel a ragged board on the flop/turn with QJs in position and then check the river.

$0.1/$0.25 No Limit Holdem
5 players
Converted at

Stacks:
Hero ($70.20)
CO ($37.95)
BTN ($25.30)
SB ($34.70)
BB ($25.00)

Pre-flop: ($0.35, 5 players) Hero is UTG [Js]
Hero raises to $0.85, 2 folds, SB raises to $2.8, 1 fold, Hero calls $1.95

Flop: [2d][6c] ($5.85, 2 players)
SB checks, Hero checks

Turn: ($5.85, 2 players)
SB bets $3.5, Hero calls $3.5

River: ($12.85, 2 players)
SB bets $7, Hero ???

Hero calls and loses to [Kd]?

PS: Bet the flop, his line screams AK or 77-TT

As played you have to call this river. I would prefer betting the flop as it will clarify things a lot more and prevent AK/AQ from getting free cards.