I'm struggling to give him any reasonable range we have anywhere near 29% equity vs. Like what else do you guys expect to see here. It's incredibly difficult for a nit to make it to this river with this line with air or with a worse flush AND decide to blast the river with it. It's also pretty inconceivable he can just randomly spazz out with a set or two pair or turn AcAs into a bluff.

It's really not hard for him to have nut flushes here. [AhAx AhQx AhKx AhTh Ah9h] is already 12 combos. Also you get to this spot with the nut flush really often which both makes his bluffing frequency even lower still and makes us pretty difficult to exploit here in theory by him randomly turning stuff into bluffs. In reality though, this just hardly ever happens vs this player type in the first place.

Folding the turn is definitely not unreasonable.