I Know This Much Is True by Wally Lamb

Dominick Birdsey, a forty-year-old housepainter living in Three Rivers, Connecticut, finds his subdued life greatly disturbed when his identical twin brother Thomas, a paranoid schizophrenic, commits a shocking act of self-mutilation. Dominick is forced to care for his brother as well as confront dark secrets and pain he has buried deep within himself-a journey of the soul that takes him beyond his blue-collar New England town to Sicily's Mount Etna, the birthplace of his grandfather and namesake. Coming to terms with his life and lineage, Dominick struggles to find forgiveness and finally rebuild himself beyond the haunted shadow of his troubled twin.
I Know This Much Is True is a masterfully told story of alienation and connection, power and abuse, devastation and renewal-an unforgettable masterpiece.