The Porcupine of Truth by Bill Konigsberg
Seventeen-year-old Carson Smith is bored of Billings, Montana, and resentful that he has to help his mother take care of his father, a dying alcoholic whom he has not seen in fourteen years. But then he meets Aisha, a beautiful African American lesbian who has run away from her own difficult family, and together they embark on a journey of discovery that may help them both come to terms with their lives.
Review from School Library Journal:
Carson's mother thwarts his summer plans when she drags him from New York City to Montana. He wasn't especially looking forward to working at a frozen yogurt shop, but it couldn't be worse than staying with his ailing (and alcoholic) father, a man he hasn't seen in 14 years. Aisha Stinson has been sleeping at the Billings Zoo since coming out to her ultra-conservative father. After a chance meeting, Carson and Aisha recognize each other as kindred spirits. Aisha comes to stay with Carson's family, and the pair soon unearth family secrets in the basement. They set off on a roadtrip to uncover the root cause of three generations of estrangement. As they pursue a reconciliation with Carson's missing grandfather, both teens wrestle with their own strained family relationships. Konigsberg perfectly depicts the turbulent intensity of a new friendship. Carson is an intensely likable, hilarious, and flawed narrator. There are no true villains in the well-developed cast of characters, just people trying to do their best and frequently failing.