I tried to find if they have a record search on their court website (the Middleton Municipal Court), as many do. Sadly, they don't.
Visiting another newspaper article on this, it appears he pled to driving with a prohibited alcohol content. This is not DWI, but sounds like a "lesser included offense." Lesser included offenses are often included by the legislature and are frequently used as plea bargains.
It may well be that the prosecutor/judge in that county (and many counties) have a policy that first time offenders may plead to the drivingw/prohibited alcohol content. That still goes on your record, just not as a DWI. It is unlikely that, after one of those, you get a similar bite at the apple.
I prosecute, and the judge has a policy not to reduce DUIs unless there's something really wrong with the state's case, in which case, he will sometimes allow pleas to reckless operation. This is NOT the norm. Most places will allow pleas on DUIs.
So, I guess what I'm saying is, before arriving at a judgment on whether or not he "got off easy," it would be helpful to know the local practice.