I just had a question that I'm not sure we know enough to answer, but is it possible that terminal lucidity is the brain understanding that it's dying, and stop

I just had a question that I'm not sure we know enough to answer, but is it possible that terminal lucidity is the brain understanding that it's dying, and stopping the allocations that prevent trouble with the body, but cause conditions like dementia? It made me wonder since the brain and body are constantly making adjustments when things go wrong, and one (possible?) cause of Alzheimer's is a buildup of plaque. Is it possible dementia is the lesser of two evils, with the other evil being death?