You could challenge the divorce based on fraud, but that will be difficult to prove, especially if you were drunk at the time. If you can't get the divorce overturned, you can file a motion to modify the custody arrangement based on a material and substantial change in circumstances. But if I were your lawyer, I would tell you to only do that if you are clean and sober and have been that way for a long period of time. You need to talk with a local attorney about the details.
Answered on Jan 13th, 2014 at 10:38 PM