Now I have no idea about his etiology of dementia, but if it’s liver failure... a liver transplant could help.
I saw an interview he did about his Mother’s dementia. It sounds irreversible... and I remember him describing her as wearing a diaper and not being aware at all. I guess my point is a transplant of a liver would be “wasted” since he will die because of the dementia. It simply sounds like his body is preparing to die since it was multiple organs... the body just starts to shut down before death.