EMT's should not play lawyer. Adult pt. who is not alert, oriented,rational & informed gives EMS implied consent to treat & transport. POA, Living will, DNR, health care proxy generally do not give the holder the right to withhold medical care not previously discussed & agreed to by patient & MD.
If the actual document is not present for EMT inspection then it doesn't exist during this emergency.
Unless the EMT actually calls the telephone number & asks to speak to Dr. "Smith" & is satisfied that it is indeed Dr. "Smith" on the line (e.g. ask for state license or BNDD number). Remember, the MD heard what Mom said, not what is really happening to the pt. I would be very surprised if any MD told me that an unresponsive pt. should NOT be transported to the hospital.
I would have my Med. Control MD call the pts. MD to verify that advice, but in the meantime I would treat & transport the pt. & advise parents I was acting in pts. best interest & would advise police that their assistance was needed in potential abuse/neglect scenario.
Most states have some sort of so-called "Good Samaritan protection for EMTs who treat & transport patients. NO one is protected if the pt. is "abandoned", even with a refusal signed by a non-custodial parent. Even if parent is legal custodian of the adult pt. there is still no legal protection for failure to obtain a rational, informed refusal of care. In my opinion no parent would ever refuse care for their son who was exhibiting Signs & symptoms of an ongoing neurological event. Any parent that did is not rational or not informed = no proper AMA refusal.
See current DOT EMT curriculum for steps recommended in obtaining such a refusal, which includes Med. Con MD speaking to pt.
Some services add a line where pt. writes "Reason(s) why I do not want to go to the hospital"
Several yrs. ago teacher signed a refusal for student hit in head by baseball +LOC, but "fine" now. Boy died of subdural hematoma. During depositions teacher testified that EMTs did not inform her of possible head injury, concussion, swelling, etc. If they had told her of possible serious injury she never would have signed refusal which did not specifically state why this was an AMA refusal.
If pt. is refusing AMA, then EMT must record medical advice told to pt during informed refusal process.