The only person ever charged in the unsolved 2021 disappearance of Navajo elder Ella Mae Begay, whose case became a symbol of the nationwide crisis of violence against Native Americans, is scheduled to be sentenced Friday in federal court. Under the conditions of a plea agreement, Preston Henry Tolth, 26, faces a maximum of five years in federal prison with credit for three years of time served. He pleaded guilty to robbing Begay and driving off in her pickup truck. If U.S. District Judge Douglas Rayes in Phoenix approves the agreement, that will effectively close the government's yearslong case against Tolth, which has been troubled by a lack of physical evidence and the suppression of a confession from Tolth. Family members said they'll urge Rayes to reject the agreement during Friday's hearing and reiterate they don't want Tolth released without him leading investigators to Begay.…