A book or short story similar to “The Ransom Of Red Chief”, by O. Henry, but in which the kidnap “victim” is a senior citizen.

I spent today with my dad. He has moderate to advanced dementia / Alzheimer's disease. I love him very much, but his short-term memory is so bad, he is continually repeating himself, particularly questions that he has asked literally one minute before. It was driving me insane!

I thought that this might make an interesting twist on a kidnap story, likely humorous, and then I remembered the Red Chief short story mentioned above.