More likely explanation (supported by no proof) is that he got into a tiff with the wife and drove home wasted. I find that more believable than the also unsupported claim about his daughter and the babysitter.
However, I don't think he got off any lighter than anyone else. I know several people who got off lighter than him actually with a super-extreme DUI. And AZ has a very strict DUI law in my opinion. Depending on circumstances, they can give less jail time and more community service, more home detention, and more alcohol classes.
For someone like him, just personally speaking, I'd rather see him do more community service, whatever that may entail. The home detention in his case is irrelevant, and so is the jail time. To most of us jail time is unbearable, but I can assure you that in many many cases it is preferable to some of the alternatives. Even alcohol classes and an interlock on your car, in my opinion, are a bigger punishment than jail time. I have had an extreme DUI in Arizona, and I can tell you, I'd rather have jail time than continued surveillance and an interlock and alcohol classes. With those other 3 they monitor your alcohol intake all the time and it can last 6 months to a year or more. I imagine he got a lot of that and less jail time. I don't think it's a bargain, I'd rather do the time and get it over with. The rest of it lasts, what-seems-like, forever.