In what way does the narrator's pride help and also hurt doodle?

The narrator is too proud to have an invalid for a brother so he takes it upon himself to teach Doodle how to stand up, walk, run and swim. His pride helped Doodle because these are activities no one ever thought Doodle would be able to do when he was born. The narrator's pride hurt Doodle because he forced Doodle to over exert himself in order to have become more athletic in too short a time. The narrator's unrealistic expectations led to Doodle dying from physical exhaustion.