You can get fatty changes in your liver without drinking regularly or too much so not sure if you can make any fast conclusions of that.
Ditto the amount of alcohol in the various tissues. They may have been coming down from the day before or going up from drinking prior to the flight.
Agree, of course, that you should not drink and fly.
And if people have a drinking problem then that should be dealt with. Alcoholics are not just unsuitable for the flight deck when under the influence of alcohol.