In this case, I don't care that he is a nurse, license implications, professional standards, etc..
Also, I want to mention that I stay out of my neighbors' business..I live in nyc..I don't care if they're bringing in hookers or smoking pot all night, etc.
To me, the concerning thing about this is that there is a drunk driver on your street. What if he hits a house, or car and injures others? What if he hits someone, a child even? What if this person is you or a loved one? I would keep an eye out and call 911 if I saw him driving and suspected he is intoxicated again.
To me, the fact that you must be 100% certain before making a report is bull. If you see someone stumbling, slurring their words, and they reek of alcohol..yes there may be other explanations..DKA etc. If it walks, talks, and acts like a duck it may be a platypus in costume. But in all likelihood this is a drunk driver and I would want to be proactive and keep myself and my family safe.