Sorry to hear of your grans diagnosis. I don't think anyone can answer that sadly, it really depends on how far advanced the cancer is and how strong your gran is but i will say, spend as much time with her as you can, sometimes that is all that is needed. I do think your gran is probably trying to protect you by not telling you and just maybe, she doesn't want to know herself. Just go with her wishes of not wanting treatment and give her a hug now and then.

Bless you all. x