Description from Google Books:

He's a boy made of fire, and he's about to meet his match. The second son in a broken marriage, Joey Lynch has spent a lifetime picking up the pieces of an unraveling family. When his older brother skips town, twelve-year-old Joey finds himself thrown into the role of protector to his mother and younger siblings, plagued by self-loathing and furious with the world. Soon, he finds himself teetering precariously close to a life of addiction that threatens to swallow him whole. The only light in his dark seas is Aoife. His boss's firecracker daughter. His classmate. And soon, something far more complicated. Aoife Molloy has always moved forward, not backward. Bubbly, strong, and self-assured, she's never feared being led astray, even by her own heart. That is, until her first day of secondary school, when she collides with a hotheaded boy who sparks a burning curiosity inside of her that only grows stronger by the day. But their friendship is tangled and complex, full of unwinding secrets and feelings simmering beneath the surface. Aoife wants to let Joey in. Joey desperately fights to keep Aoife out. But even if it takes years, what's between them is bound to combust. And their hearts will never be the same.

Snippet from Google Books:

Forced into the role of protector to his family after his older brother skips town, Joey is drawn into the world of addiction where his only hope for salvation rests on Aoife, his boss's daughter and his classmate, with whom he forms a ...