Most alcoholics have had long experience with knocking it off for good, endlessly. The temporarily sober will drink again not because they understand too much and have delved into the subject too deeply and have needlessly complicated things. Through over simplification and minimizing they fail to understand what they are up against, and do not secure sufficient answers that work well to overcome it, generally speaking.
They are no more choosing to drink when they feel good and have decided firmly not to drink again than an epileptic can decide very firmly with ironclad resolve to not have a fit.
It's part of the disconnect with reality that goes with being an alcoholic that despite years of failed experiments with self willing sobriety he/she will not catch on there's any pattern there at all and will continue to be quite sure that since they've made 8.346 days/months/years this time the problem has without a doubt been solved this time at last.
And, then they crawl back and try it yet again. Lives of alcoholics are most often spent running the maze and returning repeatedly mystified to the starting line, the next time going left instead of right, doing a diagonal this time through the maze, ending again at square one because there is no escape from what we will carry to our graves.
A very few of us have our problem removed and are freed from the usual suffering, the rest of our tribe are forced to deal one way or another, fighting against their nature or pretending what they live out through their years isn't really in fact happening to them.
Telling the newly sober to just knock it off for good and be done with it sounds good in the saying, and I know it gets to be a drag to give out bad news.
If anyone new and looking for answers is reading this...just ignore the above and fer chrissakes knock it off for good already, ok?
There, that's it fixed now.