The premise, as it stands at the moment, is that Wendell Harp will do anything for his family. This appears throughout the story as he strives to complete his book, in order to provide for his family and sustain their life in his large country house. Everything that Wendell does is, ultimately, what he thinks is best for his family.
The theme of The Killing Page is that he who hurts others will end in self destruction. What if everything Wendell does to save his family only results in tearing them apart?
Obviously the ending hasn’t been decided yet, and certainly not set in stone, but it’s definitely a possibility!