So Stef has talked about her father in various ways and had little thought asides. The most that has been established in V3 canon, I believe, is that he is an abusive asshole that loved his wife, and had zero love whatsoever for his daughter. Well, that’s true, but it’s so much worse than all that.
Why he hates Stef: Charlotte’s pregnancy with Stef was problematic, both mother and child nearly died several times. Charlotte rode out the last couple of months on strict bed rest, expecting every day to lose her life, her baby’s life, or both. And James watched this, hoping and praying that Charlotte – objectively the only person in the world he truly loves – would survive, hating the unborn child more and more every time Charlotte was in the least little bit of pain.
And when Stef was finally born, Charlotte lapsed immediately into postpartum depression, so James just held onto his life, and cursed Stef’s very existence. He saw her, from the moment she entered the world, as nothing more than the monster who tried to kill his wife.
Why didn’t he secretly have her killed off? It’s something that’s well within his power to do so. But – Charlotte loved her daughter, if only in her own way. [The postpartum depression and associated fallout meant she never quite bonded with Stef; on top of having this image of what he daughter should be, versus the child she really had.] So he wasn’t going to take away something that Charlotte wanted.
After she died…honestly? He sees her as a breathing organ donor, and nothing more. Something that could be harvested, should he ever get hurt – or just feel the need for a new kidney.