Oh yes. Years of grief.
After the first time, I made him promise not to drink at all if he were going to drive him. He insisted I promise the same, and never have. Clearly he didn't mean it. I had driven to his at 7.30pm to drop off football kit for our 6 yo's football match. House in darkness, drove to the pub, caught them coming out. He stank of beer, and to my shame I was too scared to pull our son out. Ran up the road watching his tail lights (his home is less than half a mile from the pub, ffs.) Then collared his mate in the pub who confirmed he'd had at least 2 fucking pints.
So contact reduced to 2 hours on a saturday, no overnights, and I had to school our poor son that he must never ever get in a car with his dad at the wheel. I do all the fetching and carrying.
I've upped it to 6 hours. And after all the tirades of abuse about how I'm insane and evil and he'll take him off me and teach him to hate me and he doesn't drink at all, waaa waaa waaa, lo and behold he got done for drink driving. Prick. Tried to hide it, I waited until his ban was nearly over before I mentioned it in an email. Cue more abuse.
I'm afraid you have to step up. It's horrendous, preventing overnights, and doing all the fetching and carrying, but what choice do you have if you don't want to live in fear of burying your kids.