Another theme could be the power of human kindness. The narrator shows kindness to the boy, and in return, the boy tries to be good and helpful. This kindness is something that gives meaning to their interactions in the rather desolate setting of Mannville.
The theme of deception also plays a role. The narrator initially believes the boy has a mother in Mannville, but later discovers it's not true. This shows how appearances can be deceiving and how people create illusions to cope with their situations.
One of the main themes is the idea of loneliness and the longing for connection. The boy in the story seems to be lonely and his relationship with the narrator gives him a sense of connection and importance.