My husband suffers from pd , he has had a bad headache all day , checked his blood pressure 144/93 . he is currently taking prexum 4mg each morning with his parkinsons medication , could i give him 1/2 a tablet now ?

Headache/ BP: 144/93 is not all that high and should not technically cause a severe headache . But everyone is individual. Rather than self treat with a severe headache I would go to an urgent care/ER or call his neurologist as several other issues may be at play- dehydration,intracranial pressure, infection, aneurysm. If it is the worst headache of his life go to the ER immediately as may be bleed/aneurysm