sorry about your aunt
I am going to go out a limb here.
I know it is important to respect someone's wishes
But I am not sure someone can be too busy to receive a hug and recieve the words... I love you.
as long as she doesn't feel obliged to give her time and energy
If you don't visit, maybe you could arrange to have some flowers sent to brighten her last days... with a written hug, an I love you or other support message
my thoughts are with you and your aunt
roses

an afterthought: many years ago, my father did some repair in a florist's shop. For some reason, when the owner found out it was his wedding anniversary, they gave him about 10 flower arrangements... some of them were quite large. All were beautiful. He put them in the living room. My mom smiled every minute of every day for about a week.