This story can be read as a transformation myth. How does Esteban change as the story progresses to become larger than life?
Esteban becomes something other than a dead body on the beach. The villagers create a persona for him, and he becomes almost other-worldly. As time progresses, more attributes are given to him, that inspire and motivate the villagers to lead better lives.
His size alone sets him apart, and it gives him greatness. The villagers attribute super powers to him, such as their belief that he could coerce the fish to jump into the boat. He is no longer thought of as a dead body as the story progresses, he becomes a voice that causes the villagers to want to better their own lives, and strengthen their community. Clearly, he is really just a dead body, but the villagers needed this man to realize their inner voice.