Yes, it's about how Seok-woo looks at his daughter's future.
More to the point about Sang-hwa is that he helps EVERYONE. He is the one trying to lock the door, for instance.
You actually don't need examples here. This is not a change character, so you don't see this.
Because this is a horror movie, the storyform/meaning is not really the priority. So these may not even be in there.
I think it's as simple as "Seok-woo is not a committed father."
This feels like a stretch to me. But I think that's relevant because that is how they ended this relationship—and it felt like a dumb moment. He would have run, and didn't. Totally broke me out of the story when this happened. But the filmmakers didn't have many other options. He couldn't sacrifice himself—the homeless guy does, and Sang-hwa does too. This would have been one moment of Conscious too far.
I think it's like Anti-Becoming: they recognize the breakdown in the family.
And Seok-woo finally gives over to being a father, and makes the heartfelt promise to get her to her mother.