Nathan Price is a determined, stubborn man with tunnel-vision. He can only see life through the lens of accomplishing his goals and dreams in regards to missionary work. So, his four girls grow up with a father who "doesn't see" them, and Oreanna has a husband who is so inflexible and rigid in his perceptions that she is the one that must adapt and cope in order to survive. Because of his missionary ambitions, he takes his entire family of women to Africa, during a very tumultuous political time in the country. He probably doesn't even think twice about their safety, or how well they will cope or deal there; it is the missionary work that is the most important thing. And, it is interesting that after Ruth dies, Nathan does not seem impacted; it is Orleanna that packs up and leaves. Nathan does not--again, it is missionary work that takes first priority.
Nathan's perspective in never really heard or seen in the novel, I think, because it never changes. We can guess his motivations based on his actions and words to others; he isn't impacted much by events around him, because he keeps going on his way doing what he wants to do, regardless of the logic or sense of it, or whether it harms his family or not. His daughters seem to understand him well at a young age; they know what to say and not say, and how to behave and not behave in order to fly under his radar without alarming him to their presence. They exist outside of him, separate totally from him, and deal with all of the circumstances that he puts them in without any of his help.
It isn't only his family that is impacted by Nathan's stubbornness and missionary aspirations. He refuses to change the way he plants his garden, he refuses to understand that the people are afraid to be baptized because of the crocs in the river, he refuses to pay respect to the village's "religious" man and meet him halfway. All of these serve to alienate him from his goals further, just as he is alienated from his family.
I hope that these thoughts help a bit; good luck!