Switch. The Oliver Andrews Trilogy, #1

Never having the stomach for conflict or confrontation, Oliver Andrews isn't upset about the extended school year in the small town of Fallston. Classroom dilemmas are easier on the nerves than an entire summer with feuding relatives. His parents threaten divorce-and a move back to Chicago which would uproot Oliver from the grandfather and farm he cherishes and rip him away from his only friend in the world. Maybe for good. But when the family's crisis hits a boiling point, Oliver discovers there's more to the issue than everyday family drama-and a whole lot more at stake.
Set in motion generations before he was born, Oliver falls into a tight grip of magic and mystery that threatens all he holds dear. Now he must team with unlikely-and eccentric-characters on a quest to repair his family. And save the life of his best friend.