I can personally tell you that hiding an alcoholics keys has not worked for me. What worked is setting a boundery, if you (ex) are drinking/drunk and get behind the wheel I will call the police, give them all the information. I had to do it twice, he was arrested both times, and, I would not hesitate to do it again. All hiding the keys did was to put myself in
a very abusive situatiion.
I hope that your plan works out for you.