Illustration of the novel
by Eric Emmanuel - Schmitt
He encounters "the Lady in Pink", a nurse, and talks with her about his condition. After she has left he tells the doctor that he wants to see her again, and the doctor contacts her and she talks with the boy each time she is in the hospital.
She tells Oscar that she has been hired from 20 through 31 December, which gives Oscar an indication how little time he still has to live. She tells him to consider every day a decade. This way he does not miss any stage of life, and will die normally of old age. On the day of his twenties he "marries" the girl he likes most in the hospital. Some days/decades later, after her surgery, her parents take her home, to Oscar's regret. Some days/decades later he feels weaker, but accepts that this is normal when getting old, and finally he dies. As the one he has "adopted", the Lady in Pink is upset
You can buy the original book (not with the illustration above) in Amazon