[Rap Mogul]

It seems like OP would check behind lots of draws on the turn, along with weakish made hands, maybe as strong as AK-AT, or something like J9, 96, etc..... just about all of these hands got there on the river in one way or another. So in aba's mind it's extremely likely that this river bet is one of three things:
- An attempt to squeeze out some thin value with a 6, AT, TT
- A strong v-bet with J or flush
- Total bluff

I suppose he thinks that you have to fold anything short of a flush because his line looks alot like a deceptively played flush draw. As we know brian loves stealing pots so this seems like a really good spot to represent a flush when he knows that your range is so balanced against you having one. I think you call with your entire river value betting range.