The problem is IMO this is all about levels. How bad of a guy? How little knowledge? What is the balance? Are there assistants around to teach skill sets the head coach can't?
Without understanding the baseline it is very hard to say...with all that being stated I am tired of being around assholes. I watch college coaches walk around thinking they are something special but based on the records they aren't. Coaching profession is an odd dynamic, it creates it owe little vacuum and then feeds itself.
Find a good human inside that vacuum and you will be ok - most of the time.