How much one can tolerate is probably a personal matter depending on one's own level of ignorance. But considering that with age comes wisdom, or so it should and in many cases it does, unfortunately it also comes with the insight that knowing is not necessarily a blessing. No wonder that Jesus apparently said: "Blessed are the children for theirs is the heavenly kingdom", meaning they do not know hell yet. Since the old have learnt there is hell, they attempt to flee reality with nature helping them to forget. Dementia! Not a blessing you say? Well, living with only memories of good times past and in need of care like a baby dementia is not a cup of tea one wants to drink, particularly not, when there is no loving care attached, but not knowing or to forget that hell exists is a blessing. Though I might say, hell is created by humans and their stupidity. I know, you say, why would anyone want to have dementia? Of course not! Nobody wants to be ill or die (see the fear of COV19, and the related stupidity). But there is more to illness and human's choices than ignorance and stupidity allow for. Please read the article on illness and you may understand where I come from. Only then you can tear me apart for my wisdom.