"Mick Harte Was Here" by Barbara Park

An award-winning, heartrending young middle grade novel from Barbara Park—the #1 New York Times bestselling author of the Junie B. Jones series—just right for readers of Frindle, Love That Dog, The Lemonade War, and other classic young middle grade favorites.
 
Kids aren’t supposed to die.
 
Phoebe’s brother, Mick, was one of the funniest, coolest kids you’d ever meet—the kid who made you laugh until your stomach hurt, even if you were mad at him. The kid who freaked his and Phoebe’s mom out by putting a ceramic eye in a defrosted chicken; who went trick-or-treating as Thomas Crapper, the inventor of the modern-day flush toilet; who did a wild solo dance in front of the entire school. He was the kid you’d want to be friends with. So how can he be gone? And how will Phoebe’s family survive without him?