In the novel, Dominick must contend with his sibling’s occasional psychotic breaks, one of which leads Thomas to cut off his own hand in a public library after believing that a sacrificial protest will stop the Gulf War.
Despite his attempts to protect Thomas from inadequate care following the very graphic episode, Dominick discovers a pattern of sexual abuse taking place within the hospital where his twin brother is being treated. Though Dominick successfully gets him out of there, Thomas dies soon after, seemingly by suicide.
After his brother’s death, Dominick finds out more about his family’s history and begins to heal several broken relationships in his personal life. The book ends with him coming to terms with Thomas’ passing and learning to cope with the failure and sorrow he’s endured.
HBO’s I Know This Much Is True premieres on May 10 at 9 p.m. ET.