Putting the kid's safety first was the right thing to do. Any sober parent would want that information. Hopefully she will be able to get supervised visits because of this.
How bad would you have felt if the kids had been hurt or killed due to him driving them drunk or passing out/blacking out while he was supposed to be watching them?
What exactly is keeping YOU stuck in this relationship? This guy sounds like a mess, and that's being polite.