I doubt if anyone here has read this book, but for those so inclined, you might want to consider it.
"THE OZAWKIE BOOK OF THE DEAD Alzheimer's isn't what you think it is"
The idea is that people with Alzheimer's Disease are actually experiencing brain death at a very slow rate (which if fact is what is happening).
The author discusses his experience with his wife's descent through this process and his attempts to participate. I don't agree with everything he writes, but the premise, to me, is fascinating.
Alyce, as she progressed through Alzheimer's, began living in two worlds at the same time—the "normal" physical world and the "afterlife" world, which in Tibet is called the bardo.
Alyce was a meditator but not a dreamer, the development of double consciousness came as a psychological shock to her. Elmer, however, was a "dreamer" who was familiar with out-of-body travel. And he was able to meet Alyce in the bardo and assist her in achieving fully-conscious transfiguration before her body died. Her SOUL and her soul became one.
http://www.prs.org/ozawkie.htm