Remember those teenage years? They're BAAAACCK! Seriously, he'll start really listening after the first few falls. he'll start to understand that maybe mom and dad aren't such dummies after all. I'm sorry to say there's really not much you can do but I can tell you the more you nag the worse it will be. Leave him to his own devices. tell him you still love him and always will and that you will always support every descision he makes but ultimately that it is up to him. Bottom line: you can lead a horse to water but you can't make it drink.