Did you know your brain doesn't stop developing until you hit about 24? That's a lot of years when you really have to pay attention to how you're treating your body. Hopefully it's not akin to how you would treat a waste basket. But, for those youth groups who drink as much alcohol as one should water they are hindering their brains developmetnal growth.
Talking to your kid in a safe, non-judgemental zone will be a good place to start to open the conversation on helping out. Or, if it's too extreme a rehab or detention center of some kind may be best. But alawys let them know there is someone there who truly understands and has a solution that's immediately realistic for them.