Originally posted by Reliant K1000 .I think you will want to photograph in "tribute" not "chronicle" her last days like a photojournalist.
This line sums up my thoughts on the matter as well.
It really depends on your grandmother's (and your family's) current mindset.
If she's still mentally happy and wanting photos taken, then you can likely get some wonderful images of her.
If she is not in a good place mentally (which, in her current position I imagine is the case) then it may not be worth it.
It really depends on what she, and the family, want.
I would prefer to see a family member happy, smiling, and above all, natural (I hate portraits that look posed, I refer candid shots, they're more honest and flattering to me)
My uncle passed away about 3 years ago, the photos that we tend to have around the house are the ones from when he was still healthy and happy.
We don't really look at the photos from when he was getting noticeably sick.