Tell her that when she turns 85 she may not want to die then either if there is a possibility of avoiding it, even if it is only for a few years. I’m sure there are many there that age who do not take advantage of that option because they do not desire those additional years. No one knows their actual expiration date, so an 84 year old may have another 20 years left in them, with a little assistance. 8>)
My mother in law had heart surgery when she was 86. She didn’t want to live on blood thinners, and that was the alternative.