I'm sure you've seen PLENTY of people doing stupid things, and it takes a seriously emotionally strong person to do what you do. You have my admiration.
Since she said the guy had recently bought a car, I just assumed the guy had a driver's license (which he didn't, so I don't understand why he bought a car in the first place). I've dealt with many alcoholics, and it's so sad the way it takes hold of them, and some truly are incurable.
Just from what I've seen, jail doesn't do a very good job at rehabbing anybody, regardless of the crime or drug. And from what I know, is that it's PROFITABLE to put people in jail, because of the federal money they receive per prisoner. Big business.
Yeah, drunk driving is bad. Smoking pot is bad. Stealing is bad. Lying is bad. Eating meat is bad... and on and on. While I don't have any really great solutions for what we should or shouldn't do, one thing I do know is that our society is so clamped down that we have a culture of chronic depression and anxiety.
Maybe if we had a decent healthcare system that ensures Americans get the care they need, this guy could be institutionalized and treated properly for his psychological disorders he's self medicating for?
As for prisoners (and everybody in general), I recommend a book by Bo Lozoff, it's called "We're All Doing Time." Check it out at the Human Kindness Foundation. Being in law enforcement, you might already be familiar with this book. If not, get some copies for your inmates.
http://www.humankindness.org