Was it ethical for Bernie, the manager, to quit without informing his supervisees?
supervisee: one who is supervised, who works under a supervisor (yourdictionary.com)
It became apparent that, as a manager, Jim was very attentive to the "human" needs of his supervisees.
Alternately, consider staffer.
staffer: (AmEng) a member of a staff (Merriam-Webster Learner's Dictionary)
Spindler was in the middle of his last meeting, informing his staffers of his fate.