Right, back on track.....
Greeneyes, I don't think your friend has a drink problem. She wouldn't be buying half-decent whiskey if she had, she'd be buying much cheaper stuff, and hiding it away, not leaving it out there for you to see. If she'd bought the bottles as presents, she'd have surely said so when you commented.
I think you've been very kind to this friend, but she seems to be exaggerating her poverty. I wouldn't be lending her any more money.