What about when her lung secretions were excessively thick and her blood thick, possibly even clotting, during her dehydration?
She wasn't getting much oxygen or oxygenated blood for who knows how long those last few days or hours of her dehydration.
I'm not sure what your point is here. If it's that some are convinced that the pathologist was out to lunch and couldn't tell the difference between cells that died a week ago and parts of the brain that were atrophied or replaced by other types of cells long ago, please learn more about this.
Just like the pathology report can only report on what the brain looked like during the autopsy not before death, not before dehydration.
We do have reliable evidence to be able to surmise what dehydration does to a body, brain, the eyes, tongue, mouth, etc., though.
We know that dehydration can cause alot of damage to a body. I think it's abundantly clear that some of the damage that was reported at autopsy can be directly connected to the dehydration.