Although the outcome was poignant, it wouldn't be considered a tragedy.
Because this was not the end of the novel.
The Emotion Potion was not a real antidote; as time went on, Jamie had to increase the dosage and reduce the intervals to prevent emotions from vanishing from his life.
On the last page, several decades had passed. Jamie still maintained the appearance of a young man, astonishing the world, but he was developing a tolerance to the Emotion Potion and was about to lose his emotions completely.
When the last bottle of potion dissolved in his stomach, Jamie finally realized that his desire for immortality stemmed from his acute awareness of all the beauty in the world.
Yet, he had discarded them on his quest for eternal life.
The story ends here.
It's hard to imagine Aileen would read such a thing. Perhaps the indifferent butler liked it?
