Seeing famous actors e.g. Robin Williams, and Bruce Willis suffering from dementia made me wonder in later stages do the people still aware of death? We all know death because we know the process we learn from or it’s just that we instinctively aware of it?
So these examples are actually difficult to extrapolate from for the OP’s question as these happen to be examples of some of the specific brain changes that people don’t notice.
Was just chatting with a neurologist on this.
The brain sort of accommodates for the area based vision loss. They’d mentioned an example where someone who had effectively lost half their visual field in this way would draw a clock that was round on one side but went straight up the middle instead of extending to the other side, and it looked ‘right’ to them when double checking it.
As well, the one area of language that can get messed up without them noticing is the one responsible for understanding word meanings, as it kind of ends up as a deficit in both what they say and how they hear it. They’ll just chatter on with what everyone else can recognize as nonsense words but they have no idea.
Whereas the other area that’s related to the ability to form words when speaking they very much notice. They can only speak really slowly, but they know they are speaking very slowly and get very frustrated.
So the deficits your brother had were luckily the ones that didn’t end up being very noticable and frustrating for him, but that was possibly more a mechanism of those specific deficits.
Yeah, I knew he was probably “lucky” with the particular ways in which his brain was being destroyed by the cancer - he was obviously falling apart from my perspective as an outside observer, but from his perspective he wasn’t really noticing most of the stuff that was going wrong. He knew something was amiss, of course, but the only thing that really seemed to be bothering him was his inability to use his left arm correctly (another area of his brain that was failing due to the combination of surgeries and tumor and radiotherapy). He was very fastidious about doing physiotherapy exercises for it, which gave him a sense of “fighting back” I guess. He didn’t seem to comprehend the futility of it and we certainly weren’t going to try explaining it to him.
In the end, I’m satisfied that I was able to ensure that his final months went by in comfortable and familiar surroundings, with his family members around him providing security. He seemed to recognize us right up to the last days. There are a lot of worse ways to go.