This guy is overly aggressive, have you got a lot of hands on this guy? I think I end up calling this river getting >10:1 on my money. The way things have played out you are probably against QQ/KK/QK the majority of the time, but a hand like AT / AJ / JJ / TT may bluff raise this river.

I don't know entirely if I am right here but the stats of this player make me lean towards thinking he is overly aggressive/tricky which points to bluff raising the river under the guise that he has no other way to win.