I think you don't be confused about the patients management. I do assume that the patients is already experienced by Hypertension. So, the doctor advised to give blood pressure medication undoubtedly. If the patients will deteriorated then he/doctor advice to notify MD. I can not understand one thing that is, you said the patient was mentally ill but why he refused to take BP but how he/she eager to take medication willingly? You too better motivate the patient at your high approach.