I think he filled the tub so that they would have a source of water. Here in the country we have to fill the tub when there is a storm of any kind. If the electricity goes out there is not water and that’s why I think that.
I think the man became narrator when he remembered the past
She is the wife/mother
She was pregnant when this happened and so the population was decimated by the time the boy would be old enough to remember. He had seen a dog before and begged for it’s life, he had never seen another boy. The boy had no playmates. He had is mom and dad then he just had his dad. He later sees a little boy which would be delightful in one sense. He lived in relative isolation and it would be further isolating to be the only little boy in the world. Also, he would be able to identify with the other boy. Imagine being the only man on a planet of apes for your entire life then suddenly glimpsing another man across the way. I think he worried about the other boy all the time because he was so compassionate. The boy had the man, but who did the other boy have, what would happen to him, would someone eat him, was he all alone, who would take care of him…? I think it’s interesting that the boy had such great empathy and the man had lost his. I think that is very realistic.