Plenty of people commute regularly between cities, a guy I know commutes from Melbourne to Sydney. Sports people in NZ commute between cities as well for training with the Super Rugby teams, etc.
Melbourne - Sydney is the second busiest air route in the world so there's plenty of cheap flights if he wanted to do it.
Melbourne instead of Wellington is a reasonable tradeoff deal for his family because after a hard week's work he would be home in Sydney for the weekend with the kids... oh wait.