A doctors office is the worst place to have your blood pressure taken, and if he was worried about passing a test, this wouldn't have done his blood pressure any good either.
Is there any way that he could have his blood pressure taken in a more relaxed environment?
I often think that doctors prescribing blood pressure meds on the basis of a reading taken in their office, are doing the patient a great dis-service, and are possibly prescribing meds the patient does not need, and are possibly dangerous, if it is a situational problem, rather than a physical one.