Talk to Cardiologist on High Blood Pressure.

My Father is having very high blood pressure which is constant daily 210/90 or sometimes higher. His echocardiogram, ECG, Serum electrolytes, Troponin,Creatinine, Uric acid, CPR, Urine Dr is normal. His cholesterol is slightly elevated 208. but he has constant high bp. he is living in stress for a very long time. He says i have nothing but stress. He has some problems with his business condition, His youngest son is 14 year old who is very stubborn on things. He is too stubborn that he irritates him alot even his bp is high. so can stress is the only reason of his high bp? What can be done to make it normal. also, he has sciatica which is not healing despite many things. He is not obese but over weight, Kindly plz tell us what to do his bp is not controlling despite the fact that he is taking proper bp medicines. sometimes he doesn't realize that his bp is high. he used to have high bp of 140/80 but now this is uncontrollable.