Dylan Siegel, 7, would do anything for a friend -- especially if that friend is his best one, 8-year-old Jonah Pournazarian.
The pair has been inseparable ever since they met in preschool, when Dylan learned that Jonah faces a rare battle their other classmates didn't -- glycogen storage disease, or GSD, according to LEX 18. The condition causes Jonah's blood sugar to drop to potentially fatal levels, forcing his parents to follow an inflexible, round-the-clock schedule of feeding Jonah through a stomach tube in order to keep his metabolism stable, according to ABC News.
GSD does not have a cure. And, to Dylan, that is unacceptable.
So, back in 2013, when he was 6 years old, Dylan wrote a book to help his friend and others struggling with the disease. But, it's not your typical page-turner, every penny from sales of "Chocolate Bar" -- a term used by Dylan to mean "awesome" -- goes directly to a lab at the University of Florida College of Medicine in Gainesville, Fla., which is working on a cure for the disease.
"It is now reality. It's not just a dream that these children can be cured," Dr. David Weinstein, who runs the University of Florida lab, told Fox 17.
To date, Dylan has raised more than $750,000 in the fight against GSD. Before the money began pouring in from book sales, funding for Weinstein's research was falling flat, ABC News reported. "Chocolate Bar" has given those suffering from GSD renewed hope for a better tomorrow.
"It's an amazing thing the fact that he didn't just have the idea, he followed through and he actually did it," Debra Siegel, Dylan's mom, told LEX 18. "And he was so persistent trying to get us to publish the book and sell the book. And he was really, really motivated."
You can visit the "Chocolate Bar" website to purchase a copy and learn more about Jonah's story.
Check out images of the best friends and a few pages of "Chocolate Bar" below: