Colleagues at a government-contracted shelter in Arizona had a specific request for Antar Davidson when three Brazilian migrant children arrived: “Tell them they can’t hug.”

Davidson, 32, is of Brazilian descent and speaks Portuguese. He said the siblings — ages 16, 10 and 6 — were distraught after being separated from their parents at the border. The children were “huddled together, tears streaming down their faces,” he said.