Can a landlord in North Carolina ban visitors from helping/visiting a special needs handicapped person's apartment when the person needs people to bring her things and take her to specific places? The people only come to drop off or pick up and may stay for only a short time.

NO, that landlord has no say over people coming to just visit or help you.

If the visitors have caused trouble, broken rules, or have done illegal activities they can be given a criminal trespass warning, and if they do come back on the property they can be arrested.

This is very common.

So more exact info would be needed

It would be unusual for a landlord to take a stance on who comes and goes or helps a disabled person. Could this have anything to do with parking? If the "helper" comes to visit or help within the apartment they should not be parking in the handicapped parking spots right outside the door. Those spots are for people with handicaps either to park or for helpers to pick up and deliver the handicapped person. There has to be more to this story than visitation rights.

NO - the tenant is entitled to their privacy and comforts being available to them... whoever the landlord talked to - tenant or "helper" needs to talk to local fair housing agency and find out how to handle the landlord's specific objections.