Grunch.
I don't see any leveling wars in your post. In that case, I'd fold here because of his bet size. 1.5x really looks like a value bet. If he was bluffing I think he'd shove.
The only bluff I can imagine in his range is 53 which just improved, and if he has 53 I think he shoves. And he's unlikely to call that preflop anyway.
He doesn't have A
4
. He raises that on the flop.
He's reeling us in.