In my functional phase I was drinking around the same amount as your fiancé, perhaps a little more, and was capable of stopping for the month of January without difficulty, sometimes even did January and February off. By the I was drinking 100 units a week, unable to go a day without, and my life was non-functional. I am just providing this information to show the progression of the disease, I am not saying your fiancé is or isn't an alcoholic, that isn't for me to say.