Live 1-3

Loose passive guy in his 40's limps UTG and has $140 stack
Hero raises AdAs to $18 on button covering

Flop Jd 9d Jh
Heads Up
Pot = $34

Flop checks through
Turn 4h
He checks
Hero bets $25
He calls

River 6d
Pot = $83
UTG leads $50(2 green chips)

Hero?

It's super concerning when the flush comes in and we are being lead into, particularly in a live situation. However, holding the Ad in hand, we do block a large portion of villains flushes.

Something I have noticed as well, is I have seen this player make very small bets in multiway pots on the river w 3rd pair/2nd pair type holdings, for seemingly no reason.(maybe he thinks he is blocking a bigger bet?) It's definitely concerning that maybe a J could play this way, some flushes, but then again, if he is C/Cing with some FD's on the turn here, he can definitely have missed combos, and maybe even some OESD. I'm tempted to say that AA holding a D for the blocker is just a call, and maybe we look to fold combos with no diamond. I don't have a strong read on this player, but think my reasoning is reasonable. Curious if anyone disagree's or has interesting thoughts on this spot.