In "The Scarlet Ibis," what lessons does the narrator learn from Doodle, and why is he telling this story?

One could say that the narrator learns many significant lessons from his brother such as perseverance, faith, and unconditional love. He also learned about the vast spectrum of human emotions from guilt and jealousy to grief, pride, accomplishment, and so on.

Doodle's brother may not have recognized the importance Doodle played in his life until he was an adult, which is why he is telling his story now. He uses his younger perspective to share the story, and this illustrates the immense amount of guilt he feels about the way that he treated his brother when he was younger as well as the responsibility he feels in his brother's death. However, the narrator's actions as Doodle's brother were perfectly normal for a child.

Obviously one who reads the story must understand this perspective. As a child, he could not process the enormity of Doodle's condition nor did he understand Doddle's limitations or his family's feelings and expectations. This story solely focuses on his experiences as a child and coming to terms with those memories as an adult.