My best friend and his other friend have already drunken a half a bottle of Brandy!We're only 14 help!?

Well considering you're only 14, it's illegal first off. But who knows, he could be lying right? There is nothing you can do to stop him unless you go to where he is, and obviously it sounds like you care about them. Just let them do whatever they want, you tried to warn them and in the future they will most likely see what they're doing wrong. I know it's hard to see friends do dangerous things.