Can you explain what carrier / VOIP app she uses?
Call forwarding would work, but incurs the cost of the forward to another line.
Maybe he must define what mean Local. Local = in Dominican Republic, or Locals in USA.
If he wants to be reachable from USA with USA number while is in the Dominican Republic them must apply for a plan that give you unlimited roaming incoming calls while in the Dominican Republic. Other options Google number, Magic Jack, Textnow. but all those options needs internet connections. Then we will be waitting for the next post about internet topic.