HILRY- Your aunt need a good oral/maxillofacial surgeon to evalauate her first and then make and fit an obturator for her. Sorry I don't have a specific name for you.
Obturators are a dental prosthesis designed to assist in the same way as the hard palate does: as a division between the nasal and oral cavities during speech. It is usually made of an acrylic material that is fastened to the teeth by dental clasps and can be either removable or fixed (cemented in place).
Does she live near you? Does she not have a regular dentist who can refer her to someone? I see you are in Brooklyn. I know NYU has a great Dept. of dentistry/oral/maxillofacial surgery. Perhaps, if you have no other "leads" you could start there.