Sorry to hear of your loss. Grief is worse, IMO, when we have no time to prepare for it.
My dad also died rather 'suddenly', and while I am glad he did not spend much time suffering, it was difficult to come to terms with.
When it comes to the old folks, I have more-or-less written them off.
It seems to me that old folks have on some level realized what's truly important and because of their limited time left, are willing to cut through all the nonsense.
I have seen this at work, but equally, this:
https://en.wikipedia.org/wiki/Sunk_cost#Loss_aversion_and_the_sunk_cost_fallacy
I am working toward abandoning any expectations of JW family, young and old. I perceive there is a kindness to letting someone's delusions persist toward the end of their life, especially when they have built an entire life around them.
I would merely let grandma set the pace of things, and follow along. Any decisions she makes are hers alone. Enjoy her company while she's there for you. If things get 'real', it might be a time for poignant questions...