When my mum was first diagnosed, I was worried sick about her needing chemo and the logistics of the fact that she was 200 miles from any family. My dad had died the year before, my sister`s husband had died a couple of weeks before so she was no use and it was all down to me. Anyway, I worked with a lovely girl one day who said "All I can say is, don`t worry about things until they`ve happened". It`s difficult but it was good advice. I suppose the immediate concern for your nan will be that as she has dementia, she might try to pull her drains out. I wonder if they sedate dementia patients in that instance? Anyway, one day at a time, as they say.