Someone with an MA is certainly eligible to teach at a university... as an instructor or lecturer. They can also serve as a staff member (e.g., as the Production Manager for the department). However, they are not eligiblefor tenure track positions. Which means they won't get paid as much as an Assistant Professor/Associate Professor/Professor, and they won't have the job security of a tenure position.
Outside of the academic world, it's not as strict of course. I wouldn't imagine that not having the "F" would disqualify him from much, but having it might put him one step ahead.