I was about to answer that I'm a narrative but that wouldn't be accurate because that doesn't negate that many things about me are the result of past events that cannot be changed whether I or anyone else remember them or not.
You have told us that your father has dementia that has advanced to a stage where he no longer knows who his loved ones are. Even if you weren't there to remember those things for him, he would still be your father and nothing can change that. The fabric of space-time cannot be unwoven.