using DID as a trope for horror, even if it's not actually true, and going around and using false information like saying that an elderly person (or anyone older than 10 or 11 for that matter), can develop a disorder like DID is factually incorrect. the DID part of the story wasn't wanted or needed and is just another added overused trope that's literally nothing more than adding stigmatization to an already highly stigmatized disorder and not to mention mild fearmongering.
i highly suggest not doing this shit in the future.
-sincerely, someone with DID who's tired of their disorder being played off as a horror trope :)