How can someone be lucid when their brain is all eaten up with cancer, Alzheimer etc? This is powerful evidence of the existence of the soul (mind) that survives the demise of the body.
Not really, it's evidence that when something as complex as the brain breaks it may still work occasionally. Unless you would also make the argument that a kitchen appliance with a defective control board that works inconsistently has a "soul."
There is actually an interesting debate in the field of Psychology as to whether the "mind" really exists. Behaviorists say that everything traditionally attributed to the "mind" can be explained by the brain. Freudian students of psychoanalysis, however, are firm believers in the mind. Of course, as with God, it is hard to provide empirical evidence for something that cannot be physically perceived.