I don't know why he wouldn't call a friend. In my experience I share, I just thought I was "okay enough". I wasn't experienced with drinking 3 alcoholic drinks of that caliber and it was about 7 miles to work. When I got to the car, it hadn't hit me, but quickly did thereafter. It's the one and only time I ever was to that level of intoxicated and driving.
That's why I'd be more likely to throw him in the clink for a weekend and not let this destroy his career. He has to arrive at the position that he'll never, ever do this again. Whatever it takes to get him to that point. You can destroy your and another's life. It's like playing Russian roulette.