This is a mental agility technique; refocusing your mind away from what you cannot control (powerless) and on to what you can control (powerful) i.e. your choices.
Does the language you use matter when describing how you’re approaching your condition? “I’m going to fight this disease!” vs. “I’m going to heal it from my body!” Which sounds more useful?
I once coached a cricketer who had a goal of regaining his place on a high-ranking team. His major insight was this; being 100% ‘present’ at the crease is the only thing that would get him there. Nothing else other than his best performance, moment to moment at the crease, would get him back on the team.
We shouldn’t confine ‘legacy’ to material values only, instead it can be based on human values such as authenticity and generosity.