If the blood pressure was severe enough to simply overwhelm the heart acutely and put it into heart failure control of the bp should be enough to alleviate the heart failure. If the elevated bp is longstanding to the point where it has permanently weakened the heart the problem may be a little more difficult to control. Still if he is otherwise healthy with normal kidneys there are plenty of strong medications available to help his heart compensate to a normal life. The cause for the heart failure(bp, blocked arteries, toxins) needs to be fully addressed to prevent further damage to the pumping part of his heart since there is an eventual threshold beyond which survival is problematic.