Hi, My 47 Year Old Male Partner Currently Has 143

Hi, my 47 year old male partner currently has 143 over 80 blood pressure. It was elevated more than this 20 minutes ago whilst we were out walking in the hot sun. He is on medication and has to go back to Doctor in two weeks. His medication doesn't seem to bring his blood pressure down. He feels dizzy frequently and has bad headaches. He also has bad 'turns' that can last sometimes up to 15 minutes where his body all of a sudden feels really hot. We call them hot flushes. How high, or what is the range of blood pressure when a person should seek emergency help ?