The Boy Below 2003 on netflix

Anders is 10 years old and has one great passion: diving. He is going on holiday to Greece with his dad, whose behaviour is erratic due to his heavy drinking. They are secretive about their holiday, because the social welfare would stop them going if they knew. Only Grandmother knows. In Greece, Anders takes up his diving, but Dad isn’t able to keep himself sober, and consequently Anders has nobody to turn to.