most likely the headache is because of high bp.
what are the levels you have recorded?
there is no permanent cure for high bp.
he should take antihypertensive Medicines daily as prescribed by a physician.
suggest you to get it checked out if he is not on medications.
bear in mind that heart attack and stroke have a very strong association and almost always occur in patients with hypertension.
I he is prescribed medicines, he should take it daily. no other option.
consult a physician and get him checked out.