So flying by the seat of my pants here with developing this guy but maybe he knew something about the supernatural but not as much as he thought he did when they met? ba
I feel like he'd have maybe developed a bit of his moral compass in her company? He'd probably make up for his lack of proficiency ( not being a badass hunter) by being well prepared etc.
I do think him having some guilt and angst over what happened to her would be great, maybe he short of disappeared after it happened, couldn't find the words etc.