I've hit rock bottom before, and my friends wanted to turn me in to the authorities and my work for abusing marijuana (seriously, it was an HOURLY thing). It would have destroyed my life if they had. Instead, they just stopped being my friends. I literally lost all of my friends because of my drug problem. I honestly don't know what's worse.
Then again, this is cocaine we're talking about. Far more harmful and far more illegal as far as I'm aware. I'd tread cautiously, but because she isn't listening to anyone and can't be medicated for her disorder... that's a tough one.