Parkinson’s Disease may be a red herring. I believe it is not a type of dementia, although a Parkinson’s patient might be at higher risk for dementia as a separate diagnosis.
I think you are correct in that Parkinson’s is a red herring. It is often accompanied by dementia, but not always. Biden supporters would be happy to have people believe he has a physical impairment but is mentally OK.
The one thing that Biden critics should repeat over and over is that Biden cannot speak with knowledge without reading a teleprompter or notes