I'm with Crankin.
Your brother can't count on a change, though it may help to change his diet there are no guarantees. I eat a relatively low fat diet with very little meat. High fat, low fat, high carb, low carb, it doesn't seem to effect my cholesterol levels much at all. I still have to take the drugs. Even when I went ultra low fat my cholesterol levels didn't drop enough to drop the meds.
My BP is high. Exercise made no difference at all. I eat a low salt diet. It is a big enough problem that I think I am going to have to change my BP meds as the old ones are not working quite as well as they once did. And this is exercising more than I have ever exercised in my life and this is being thinner than I have been since 1980. My sister is a hair taller than I am and weighs almost twice what I weigh. Her BP is low.
Trek Madone 4.7 WSD
Cannondale Quick4
1969 Schwinn Collegiate, original owner
Terry Classic
Richard Feynman: “The first principle is that you must not fool yourself and you are the easiest person to fool.”