When you see the letters z”l after a person’s name, it means “may their memory be for a blessing.” The wish seems almost unnecessary here: Nelson Mandela was a blessing in life to his country and to the world, and his memory will certainly be for a blessing as well.
He did not seem to make his choices out of fear, no matter how legitimate the reasons for fear. If more of us could learn that one thing from him, our world would be a better place.