The narrator shows his pride every time that he tries to "improve" Doodle. He teaches him to walk, run, jump, swim, and row. All of these things are done out of his own selfish pride. He does not want a brother who is not "all there" as he states in the beginning when baby Doodle smiles up at him for the first time.
The first link does a good job explaining the overall theme of the story. It includes some information about his pride.
when he gets his charzard