Hi IF,
Thought I'd try and impart some of my "research" into drinking to see if it helps any. As a performing alcoholic, I saw my LFTs go dangerously off the scale. These tests are used by docs to give a rudimentary guage of how much distress your liver is in. Sometimes, quite arbitrarily, they would show up as fine which I seized upon as a justification that my drinking was fine. It is by no means definitive.
It's a common misconception that you have to drink a bottle of spirits a day, drink alone, or in the morning to be a true alcoholic. Indeed, I know people who regard themselves as chronic alcoholics even when they've had long periods of abstinence or just a couple of beers in the evening. Also this units business is misleading because everyone is affected differently according to genetic make-up and other health factors. Finally, the liver is just one of the organs affected by long term heavy drinking. There are many resources out there describing in detail global effects of alcohol abuse on the body.
At the end of my drinking I was hospitalised with acute pancreatitis, which could have easily killed me. It wasn't pleasant.
However, like another poster mentioned, your aunt has to decide for herself that her drinking is causing her problems but for you I would def recommend Al-Alon for friends and family of problems drinkers. They are a wonderful fellowship, which I have also (as well as AA) attended as my late husband died as a direct result of where drinking took him mentally, physically and spiritually.
I hope you and your aunt find some peace.
Much love
kxxx