Cause?
There is a past link on FR that mentioned dementia.
Don’t know the cause, but he battled dementia for years.
Covid. /sarc. Just guessing but covid seems in vogue for all reason of death lately.
It has been cited in the past that he had Amyotrophic lateral sclerosis (ALS),
also known as motor neurone disease (MND) or Lou Gehrig’s disease.
This progresses over time to stop other body functions.
https://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis