What is the main conflict in I Know This Much Is True by Wally Lamb?

I Know This Much Is True by Wally Lamb is told through the eyes of two narrators. In the 1990s, Dominick Birdsey, forced his entire life to take care of his mentally-troubled identical twin, Thomas, has his life shattered when Thomas cuts off his right hand as a religious protest against the growing Iraqi war. Divorced from a women he still loves because of the toxic anger that Dominick readily admits, grieving years after losing a baby to SIDS, working as a house painter after he washes out as a teacher, and living with a woman who drives him crazy, Dominick does not need this additional burden, but he undertakes fighting a politically-motivated bureaucracy, which consigns Thomas to a high-security mental institution. Meanwhile, he begins psychotherapy, seeking to control himself and understand the scars left by his and Thomas' childhood and youth.