Don't ignore the physical signs besides behavior. The alcoholic here now has to shower several times a day because the alcohol seems to change his body chemistry and any scented product on or near his body. It's not unusual for him to smell like day old stale cologne 4-8 hours after continuous drinking. He has to shower before going to the gym especially in the morning. He complained in the past he was being called out on body odor by members and blamed it on the washing machine and detergent years ago. Apparently that issue has flared up again over the last year.
And behavior isn't always about staggering, slurring etc. I notice extreme mood swings and frequent chippyness from a lot of caffeinated/energy drinks to counter the sedation effects of alcohol.
It's just a way of life to them. Just like we get up and go through the day sober they go through the day buzzed or seeking that next high-that goal/focus is extra incentive to put on a show to get what they want. There's also act like they don't have a problem or have it under control but this tact only tends to work among some friends and family.