The deep, personal material of the latter half of your life is your children. You can write about your parents when they're gone, but your children are still going to be here, and you're going to want them to come and visit you in the nursing home.
Those who do not have power over the story that dominates their lives, the power to retell it, rethink it, deconstruct it, joke about it, and change it as they change, truly are powerless, because they cannot think new thoughts.