CHICAGO — Marshall Douthard Jr., 19, can picture himself on the expansive balcony of the single-family home that looks out over Chicago’s Garfield Park neighborhood, a house that he helped build. “Just walking out in a robe, with a cup of coffee in the morning,” he said. “Even in the winter?” I asked. “That’s the best time,” he said. It won’t be his house, but Douthard was envisioning himself …