It would be easy for me to say that Bob should follow his writing dream since he's already got all the prof cred (and money) he needs from lawyering. BUT. If I were in his shoes, what would keep me stuck on the horns of this dilemma is that he's GREAT at being a lawyer, and he knows he's helping people (which tells me he's made the hat trick: a career that's rewarding financially, intellectually, and socially). Not so easy to give that up.
But . . . does he really have to? Isn't there a middle ground here? Reducing his hours and client load and writing in the time that frees up? Four hours a day — heck, two hours a day — spent writing can add up to a novel draft in less than a year.