Good for him, but that is a dangerous thing to attempt. The drunk may have also had a gun, and it could have turned out very badly.
Back about 15 years ago, I was going to work when a car almost sideswiped me, as it passed, on I-20. They were all over the road, and they just happened to take the same exit as I did, and pulled into a 7-11. It was two young women, and they got out and staggered into the store. This was about 6 a.m. I parked my truck behind them so they couldn't drive away and called Arlington PD. The girls came out and began yelling at me to move, but I told the them that the police were on their way, and I would move when they arrived. They then began crying and begging, which did no good either. When the police arrived, I told him what had happened, and pointed out the one who was driving. He had me write a statement about what I had seen, and he spoke to the store clerk. They both went to jail. I assume the passenger for public intoxication, and the driver for DUI. I was never contacted for any testimony, so I don't know the outcome. But, I would not ever attempt to drag someone from their car. JMHO
Take away the Second first, and the First is gone in a second