Lmao
It’s common for demented people to cling on to what matters the most to them. When my grandfather got dementia the first thing to go was bookkeeping and accountancy but he remembered his great grandchild and how proud he was of them until the very end. Similarly with Genocide Joe the desire to murder brown people still burns as bright as always.
There was an episode of This American Life in which a physicist with Alzheimer’s forgot how to draw/read a clock, but because he spent so many years doing analysis and problem solving, was able to reason toward a procedure to do it anyway. And was able to comprehend his own decline if he reasoned through it.