So I'm thinking about resigning from my current position sometime in the near-ish future. I'd like to let my boss know he's the reason I'm leaving so he can (hopefully) improve so it doesn't continue to negatively impact my coworkers.
For context, my boss is always working (for instance, he'll wake up at 3am, can't sleep, and send emails or work late into the night sending emails or texts to us). There's somewhat an expectation for his subordinates (me and my coworkers) to always be available as well and be ready to jump at every notification like it was the most important thing on earth. He says he understands that we are hourly and that we have lives outside of work, but this expectation still lingers. His managerial style is also that of a micromanager–he'll ask us to do things that are either part of our daily tasks or that we are currently working on. He'll hover over us as we're trying to troubleshoot something for a customer and give suggestions as we're doing our job (and didn't ask for his help whatsoever). He doesn't seem to trust us to do our jobs but is too busy to do all of it himself.
Two of my other coworkers have left in the past 4 years, and I'm going to be leaving at some point this year. I know for a fact that the other two left because they couldn't stand his micromanaging and how he overworks us. I like where I work, I like my job, and I like my coworkers. My boss is just making my time miserable.
TLDR;; boss overworks us, doesn't trust us, and is a huge micromanager. how do I tell him so he can hopefully improve to spare my coworkers?