No Falling

Jerry "Wyatt" Donovan is the 4th and last son to parents who were done parenting after the third born. He's a geeky kid who's abused by his older brothers and bullies at school. He spends many summer days locked in a bathroom to escape the abuse.
His clothes are hand me downs. In his whole life he never had anything he could call his own, except his bike.
His sole escape is trail riding with his friend, Tom Murphy in an abandoned construction site the size of a small city. One day, he rides a new trail and discovers a portal into a way station where he meets Bob, a cosmic cop. Bob explains to Jerry that he has a family in another world; that he's part of a wizard family, and an evil half-brother has taken over the kingdom and is holding Jerry's real father hostage. It turns out Jerry is the only one who can free his father and remove his half-brother from power and save the day.
Along the way, Jerry discovers a sister he never knew he had and begins to develop powers far beyond anything he could have ever imagined. Jerry finds that not all friends are real, and not every enemy is evil.
The first half of the book is Jerry/Wyatt assembling his team and preparing to make the trip into this other world. The second half of the books is his journey through this new world into Utopia to break his father out of the prison camp and remove his half-brother from the throne.
Along the way, he has to contend with werewolves, dragons, evil fairies, trolls, a rival family's interference, and a witch named Amanda Kreulwich.