The story is memorable largely because Doodle's character is unforgettable. A gentle, sensitive, and sweet-natured child, Doodle is abused physically and emotionally by the brother he loves. Doodle's need for his big brother is so great that Doodle tries hard to please him; Doodle dies trying to please him. He cannot defend himself against his brother's unrealistic demands or his bursts of cruelty. Doodle evokes great sympathy--for his size, his frailty, and the physical disabilities he struggles to overcome. He also gains our sympathy because he is so innocent, he suffers so much, and his death is so tragic and unnecessary. The dramatic conclusion of "The Scarlet Ibis" remains with the reader long after finishing the story. It is shocking and tragic, and the picture of Doodle's small broken body lying in the rain, cradled in death by his brother, is powerful and more than poignant.
I think it very memorable because we can all identify with Doodle in one form or another.