So what if you got alzheimers or non-fatal brain injury?

Yeah I wondered this too, and I came to the conclusion that it must be that the stack interfaces with the biological brain in such a way that it controls the brain and takes over its functions, but it is not actually affected itself by the brain, so if something goes wrong with the biological brain, the stack would remain intact. Perhaps people don't even get diseases like alzheimers in this world because the stack does all the memories and everything, the brain is just used for motor control and sensory input and output? So if the brain started getting diseased or whatever, it would just mean the stack couldn't take down more memories, but once the body died, the stack could be put in another body and the person would remember whatever was the last memory they managed to put down before the brain was corrupted?

just rollback to an earlier savestate