Still Waters by Jennifer Lauck

Separated from her brother Bryan, and passed from caretaker to caretaker, Jenny discovers - as she rebels her way through high school and into adulthood - that the past can never be truly locked away forever. She survived the stunning traumas of a lost childhood, but survival may not be a way of life. Now the secrets, lies and loneliness that once imprisoned her are brought into sharp focus, where an adult Jenny can make her peace at last. But one more mystery demands her attention: the quiet troubled soul of Bryan, who, lacking the inner strength of the survivor, chooses a sad and sorrowful destiny. And Jenny must dig deep to find the one bond that held them through the years, and the one reason any of us have for enduring: love.