Hi.
I have Mets cancer , so had in breast ,lymph nodes, a spot in liver and hip .
Both of my parents are 80 and 86 , they have their own health issues.so for me personally I told them about the breast and lymphs ,a bit hard to hide a double mastectomy,but I have not told them the rest.
They are worried enough ,I do have to be careful with what I say and medical app.,etc I guess it depends on how much you are willing to hide and pretend around her.
But it is up to you ,but if you know any of her good friends might be helpful to have around when you tell her as a support for you and her.
Good luck