I am no doctor. But my gut suggests two BIG things: exercise to get as much oxygen into your brain as possible (and give you body control and confidence). And learn how to fall AND get up. Because when you do those things you will not fear falling. Because the fear of falling is, interestingly, one of the things that causes us to fall. Why? Because we avoid doing the things that give us the body confidence to handle falls. It makes no sense and all the sense in the world. While this is your journey, I might look into local PTs, find a trainer who specializes in working with older folks, explore yoga.