I was thinking he does have a fair amount of Tx in range that may include some FD also.
AT/A5 also comes to mind and this board texture makes these range call down often.
So, if he is bluffing here, it is super hard to call.
Thoughts?
PokerStars - $0.25 NL FAST (6 max) - Holdem - 6 players
Hand converted by PokerTracker 4
BTN: 102.68 BB (VPIP: 30.77, PFR: 7.69, 3Bet Preflop: 0.00, Hands: 13)
Hero (SB): 246.56 BB
BB: 131.48 BB (VPIP: 20.00, PFR: 14.78, 3Bet Preflop: 4.35, Hands: 119)
UTG: 100 BB
MP: 100 BB (VPIP: 17.60, PFR: 14.66, 3Bet Preflop: 9.35, Hands: 350)
CO: 136.48 BB (VPIP: 13.33, PFR: 13.33, 3Bet Preflop: 0.00, Hands: 16)
Hero posts SB 0.4 BB, BB posts BB 1 BB
Pre Flop: (pot: 1.4 BB) Hero has 7♠ 7♦
UTG raises to 3 BB, fold, fold, fold, Hero calls 2.6 BB, fold
Flop: (7 BB, 2 players) 7♥ 9♣ A♣
Hero checks, UTG bets 3.76 BB, Hero raises to 10.12 BB, UTG calls 6.36 BB
Turn: (27.24 BB, 2 players) 8♠
Hero bets 19.48 BB, UTG calls 19.48 BB
River: (66.2 BB, 2 players) 6♠
Hero checks, UTG bets 67.4 BB and is all-in
https://forums.pokerstrategy.com/forum/thread.php?postid=2735326#post2735326
The hand above seems like a similar situation.