I fold the river. You have a one card blocker to both Front door and Back door FD, which eliminates a good chunk of the draws available. Some of those busted draws are pairs that he might have haphazardly turned into a bluff, the flush draws that are both no pair and not A
Q
are few and far between. He could have also made a weird bluff with something like 44/55 of which you still can't beat.
Of the value hands, he can have T2/62/32, K
X
or K
X
, even some KXo which you probably don't have enough data points to rule that line out.
Some nonzero% of the time, he can show up with 22/33/66/TT/AK/54. The busted flush draw no pair is just such a miniscule portion of the described range.