The silence on this issue will be deafening.
My father has Alzheimers and is in-and-out of dementia.
He has a medical problem, one that is not immediately life threatening that requires a very involved surgery. Because of the complexity and length of the surgery and the amount of anesthesia involved, it means he may never recover his sensibilities or any lucidity, and may be totally demented afterwards.
In his present state he is aware of the problem. It scares the Hell our of him. He wishes he were dead.
His doctors ( yes, plural) and I agree that he can live for years with what is ailing him but he may have only a few months or at most 14 months with the Alzheimers. It is not worth losing his sanity to have him undergo an involved surgery that will not do anything to truly extend his quality of life or length thereof.