Is he an adult and not a mentally disabled person with a 50 IQ score? Is he the oldest high schooler in the country and the next day a school day?
If you answered yes to the first question and no to the latter two questions then it's appropriate for him to do whatever he wants (unless it involves felony drunk driving; physical and/or sexual assault; etc...). Is his nonsense lifestyle effecting his employment status? That's a different question.