It is possible but generally special circumstances are required, such as special key words to prove that this is in fact the individual he or she claims to be; and the key words used to identify have to be approved in writing by the patient.
My experience is that it is best to have a a written authorization is best.
I am licensed in New Mexico and Pennsylvania, and therefore any discussion of issues related to other states must considered within that context. In addition, my comments are not intended to create a legal representation but merely to respond to the limited facts presented by the question. Any opinion herein is not meant as a precise statement of legal rights or as a recommendation of any particular course of action. A more complete legal review can be obtained through local counsel.