There are of course many different messages or potential themes that you could take away from reading this excellent story. One of the key themes of the text is the conflict that is presented between love and pride. Chiefly of course this is explored through the relationship of the narrator and his brother, Doodle. Although Brother clearly loves his disabled younger sibling, at the same time his relationship with Doodle is impacted by pride and the way that this can lead to cruelty. The narrator clearly feels a sense of embarrassment at Doodle's various limitations, and does everything he can to train Doodle so that he won't be different from everybody else. We see this clearly after the demonstration that Doodle gives his parents when he shows them he has learnt how to walk. When he sees this, the narrator begins to cry. Note what the text tells us at this stage:
"What are you crying for?" asked Daddy, but I couldn't answer. They did not know that I did it for myself' that pride, whose slave I was, spoke to me louder than all their voices; and that Doodle walked only because I was ashamed of having a crippled brother.
The narrator's relationship with Doodle is clearly driven by pride as well as love, which forces him to push Doodle to ever greater feats of physical achievement. It is this sense of pride of course that leads to Doodle's death, as the brother, in spite of Doodle's obvious sense of exhaustion, continues to train his brother until Doodle actually dies from the physical strain. Thus the message of this story concerns the way that often in our closest relationships other, more negative emotions can be incredibly important. We need to be aware of these emotions and feelings in order to ensure that they do not destroy both ourselves and the relationship.
Only have "love" is not enough. We have to know how to love. We need to use both our heart and brain to give love. Without proper method, we may not make love work as expected.