For anyone interested, an update:
I got the job! They're offering me a significant raise and the capacity to work from home. But I couldn't officially resign today because my boss didn't even come into work today (nor did he tell anyone he wasn't coming in) because- get this- he "doesn't want to bring the burden of the workweek into the weekend" so he's taking every Friday off until further notice so he can "clear his mind before the weekend".
Meanwhile he's forcing his four remaining employees to put in unpaid and unaccounted overtime. Oh yeah, and he's firing the cleaning crew so his designers (including a certified professional engineer) can rotate mopping floors and scrubbing toilets.