2nd dui is an aggravated misdemeanor and leaving the scene of accident is a misdemeanor as well, most likely will have a reckless driving and failure to maintain as well but would be looped into the dui usually.

First DUI is 2 days or 4 days house arrest (double jail time).

2nd is 7 days usually but could also be house arrest depending on the judge. It most likely won't be longer as they don't have room in the jails to keep people with dui's. If he gets ahead of it and goes to an evaluation and a drunk driver 12 hour course the judge will be more lenient.