If you have someone looking for a happy ending book about someone going above and beyond overcoming adversity, The Running Dream, by Wendelin Van Draanen, is what you need to reach for.
Jessica wakes up in the hospital after a severe car accident. Her leg has been amputated. Her days of track team and running seem over. She struggles with adjusting to her new life: simple tasks are difficult, she's behind in school, track is no more, insurance woes plague her family; she just can't seem to put one foot in front of the other (don't groan, the book is chock full of puns like this!). But slowly and surely Jessica adapts to the changes in her life and takes on new challenges as she learns what is truly important in this world.
Also, the constant stream of successes for Jessica as she works toward her happy ending might bother some readers for being unrealistic. The way she soars through recovery sometimes makes it seem like her bigger challenge is her crush on a boy, not her missing leg. But it didn't bother me, because I liked feeling uplifted by the character's successes, particularly her new friendship with a fellow classmate with cerebral palsy.
I'm not a runner, but being from Boston, this book really resonated with me. The cynic in me could say that this novel is overly optimistic at times, especially with how fast Jessica makes her recoveries and easily (as easy as it can be with one leg) overcomes every obstacle she faces, but the stories of hope that keep coming from the Boston Marathon bombing victims erase my cynicism and make me appreciate the hopefulness of the story.
I think The Running Dream could work in so many displays: sports, marathons, health, quick picks, etc. It is a fast, interesting read that incorporates overcoming adversity with typical teenage obstacles that young adult readers will appreciate reading, with or without an interest in track.