An alcoholic is an alcoholic is an alcoholic.
So whether they are "functioning" or laying in the gutter, if you are trying to "understand" them, their thinking, their reasoning, their gaps in memory, their lying, their choice of socks, their whatever, and you are not accepting in the forefront of your mind that you are dealing with an active alcoholic, then you will likely be baffled by their answers or behavior.
Alcoholics are messed up thinkers! All addicts are. Addiction is a brain disease.
Remember if someone's drinking, lapses in memory, lying, is a problem for me then it is a problem. Period. For ME! I don't need to convince that person that it is a problem. I just need to accept them as they are and figure out what am I going to do? What is in MY control that I can change so that my life starts looking how I want it to look?
peace-
b