David Siegel/ABC News

Most kids would do anything for their best friend and Dylan Siegel is no exception. The 8-year-old boy has raised $1 million to help research the rare disease afflicting his best friend.Dylan's best friend Jonah Pournazarian is one of 500 children in the world suffering from glycogen storage disease type 1B, a liver disorder that has no cure.Back when the boys were 6, Dylan wanted to help raise money to find a cure. His book, "Chocolate Bar" has sold nearly 25,000 copies in 60 countries and, as of this week, has raised $1 million."Chocolate bar" means "awesome" to Dylan. "Disneyland is so chocolate bar," the book starts out, according to ABC News . The last page says, "I like to help my friends. That is the biggest chocolate bar."Every cent raised from "Chocolate Bar" to a research team at the University of Florida. ABC News reports that proceeds from the book has financed the hiring of a new geneticist, studies resulting in new gene-therapy treatments.