I have seen first had what Dementia can do to the brain, and most of the times Alzheimer too... so I will be very hesitant to do this for large quantities of Bitcoins. If
anything like this happens, I want my family to have access to my coins, and if this was committed to memory, they would not be able to use it, and it will be lost
forever. The old trusted methods of printed documents, protected with lamination, is still my preferred method of storing my private keys.

{multiple copies}