Writers have to be observers, interpreters, translators of experience.
Yet all of that relies on memory.
Our brains streamline experiences into nice, neat packages. These make more sense than the raw material of life itself, the material that gave rise to the memory. What a writer does is streamline the material even more, so that another person can understand and follow the storyline.
What, then, happens to stories when memory falters? Or, as with Alzheimer's, becomes unreliable and spotty?
If human beings are hardwired to be storytellers, why do we also attempt to blot out memory with drugs or drink?