At three in the morning, Gabe Mendoza woke and listened for his father. Outside the house in North Komelik, a village on the Tohono O’odham Indian reservation just west of Tucson, night extended like a deep well into the open Sonoran Desert. The year was 2007, and Gabe, then 27, had left his job to become the full-time caretaker for his father, Wilfred, who suffered from diabetes and moved around in a wheelchair.