So it is not about the brain. But consciousness.
How often do I need to tell you?
Don't believe?
https://medjournaldaily.com/man-with-90-brain-loss-living-a-normal-life/
For comparison a normal brain:
https://www.elitereaders.com/missing-brain-still-alive/
https://www.iflscience.com/man-tiny-brain-lived-normal-life-31083
https://www.cbc.ca/radio/asithappens/as-it-happens-thursday-edition-1.3679117/scientists-research-man-missing-90-of-his-brain-who-leads-a-normal-life-1.3679125