When parents keep repeating themselves?

8 years ago when I became my mother-in-laws primary 'hands on' caregiver after my father-in-law died, and she repeated every singe story 80 times in two hours... YOU LET IT GO! I figured out not to correct her, since her reasoning switch had malfunctioned. I acted like that's the first time I'd ever heard it, cause to her it was! Now she's in a memory care unit and she and I no longer go on road trips together. She no longer repeats the same stories to me, because she can no longer remember those stories or me for that matter. I miss the times she repeated herself 80 times in 2 hours. Dementia/Alzheimer's is an awful disease.