Hello, High blood pressure is one of the most important risk factors for stroke and heart attack. Brain damage may have occurred from lack of oxygen due to the heart stoppage. I would need more information in order to assess his condition. However, you should be able to speak with the doctor in charge of his case and get this sort of information just as well since they also have the advantage of being able to physically examine him, look at test results, and call in specialists to help guide treatment. Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. Dariush Saghafi