Dear member,
A manager's job is getting the job done through people. In your case, the number of people reporting to him is too less. However, it does not matter. You can give him a designation of either "Branch Manager" or "Branch in Charge".
Whatever, the designation you allot to him, the real challenges that could come up are different. These are as below:
a) The Regional Office or the Head Office should not bypass this person and deal directly with his subordinates. Their direct dealing could erode his authority.
b) The person should not have just a designation but sufficient authority as well. Sans adequate authority, if he is often required to call the regional office, then his stature could reduce to a supervisor in the eyes of his subordinates.
c) As very few subordinates report to him, he will have one more challenge of maintaining a discreet distance with his subordinates. Managers are expected to exercise strict control. However, the forced closeness may create hesitation in the mind of the branch manager, and he may not be able to enforce discipline even when he is required to. He may not dine with them or share WA jokes with his subordinates to maintain a mental distance.
Thanks,
Dinesh Divekar