I have a digital journal of all drinking activity. I keep it in an online Google Doc so it's 100% secure and can't be lost or stolen. I kept any receipts I found for alcohol, and when the receipts disappeared I started taking date-stamped photos of the empty alcohol bottles (again, saving them on a secure online account). I have some video from a couple of really bad episodes as well. In my mind, evidence is evidence and the whole point is to eliminate any reasonable doubt as to the alcoholic's condition.