Why does the boy wish that the other little boy was with them?

The boy sees the other little boy as an extension of himself. He has his father, the other boy has no one. He has a bit of food, the other boy is hungry. This scene is one of compete compassion..... the boy isn't yet jaded. He still looks for the good in the world, and above all else, he still wants to help.

The Boy:] What if that little boy doesnt have anybody to take care of him? he said. What if he doesnt have a papa?

[The Man:] There are people out there. They were just hiding.

[. . .]

[The Boy:] I'm afraid for that little boy.

[The Man:] I know. But he'll be all right.

[The Boy:] We should go get him, Papa. We could get him and take him with us. We could take him and we could take the dog. The dog could catch something to eat.

[The Man:] We cant.

[The Boy:] And I'd give that little boy half of my food.

[The Man:] Stop it. We cant.

He [The Boy] was crying again. What about the little boy? he sobbed. What about the little boy?