Getting loaded at the worst possible time is one of the characteristics of the alcoholic. There is nothing sane or reasonable about it, it just the nature of the malady. AA suggests that this behaviour will repeat until the alcoholic undergoes a complete psychic change ( change of personality) sufficient to recover.
It is quite possible, based on experience, that this bender was well on the way before the stressful situation developed, and would have happened anyway. It's just in this case the alcoholic can rationalise the drink is his own mind, after all, wasn't he in a situation where anyone would drink? It's a really credible excuse, but if it wasn't available I suggest he would have created another one. The alcoholics imagination is almost limitless in this regard.
The real reason probably was that,though not drinking at the time,the alcoholism was not arrested and the pressure from his alcoholic reactions to day to day life was building. It happened to me many times.
Yet strangely, since having that psychic change, much more dramatic life events that happen in life have never lead me to consider a drink. Quite miraculous really.