Fitzgerald is faced with a difficult task at the end of "Benjamin Button." He has to describe the death of a man who is getting younger and younger every day. He’s created a fantasy, which means he has to define all the rules, and determine the way things work in this fantasy world. What will happen at the end of the story? Will Benjamin disappear? Will he become a fetus? What will Benjamin look like at the very end of his life?
Let’s go to the text:
There were no troublesome memories in his childish sleep; no token came to him of his brave days at college, of the glittering years when he flustered the hearts of many girls. There were only the white, safe walls of his crib and Nana and a man who came to see him sometimes, and a great big orange ball that Nana pointed at just before his twilight bed hour and called "sun."
[…]
And then he remembered nothing. When he was hungry he cried—that was all. Through the noons and nights he breathed and over him there were soft mumblings and murmurings that he scarcely heard, and faintly differentiated smells, and light and darkness.
Then it was all dark, and his white crib and the dim faces that moved above him, and the warm sweet aroma of the milk, faded out altogether from his mind. (2.1.8-11)
What we see is that Fitzgerald avoids the crassness of any overly physical detail and instead describes Benjamin’s death from Benjamin’s point of view. The result is a subtle, artistic, and poignant ending that tips the story’s tone from the realm of satirical fantasy into real, emotional, and bittersweet drama. You can check out our discussion of "Tone" for more on the mosaic of moods to be found in "Benjamin Button."