travB
It is a good thing to use this forum to ask questions, but I honestly believe you should convince your future airplane owner to use the services of a professional.
I mean: a professional
consultant. In theory, all of us here are professionals and we all have our opinions and preferences. But the Aviation Consultant will be able only to listen to your boss' needs, sort out the unnecessary from the necessary / desirable and represent her/him in negotiations with airplane sellers. Worth every penny.
There are many reasons to buy a SE turboprop and there are equally many to buy an entry level jet. What's the best for you, this consultant will find out.
The good news is: there are people out there willing to invest in airplane.