No one has any idea what his BAC was. All we know is what he's been charged with. And just because someone has had a drink doesn't make them drunk.
Is it stupid to get behind the wheel after having a drink? Sure is. But let's be a little realistic here for a moment. He probably wasn't wasted or sloppy, just speeding, and when you speed bad things happen. Whether he was drunk or not, if he was driving at a high speed and hit a curb the car was going to flip no matter what. It truly is a tragic event, very unfortunate. He just as well could've been sober and driving while texting and suffering a similar fate. I'm not saying he was, just giving another example.
And I am by no means advocating drinking and driving. It's extremely dangerous, and puts everyone one the road at risk, not just the person who has been drinking.
But as someone stated, it's easy to sit on a high horse when it's not you or a loved one involved. Mistakes happen, and unfortunately this one took a life.