With a sudden onset and diagnosis like that, it is completely understandable. Home is where most people would want to be and I am sure everyone wants to spend as much time with him as possible. Just keep in mind that home aid (or Hospice) still might be a helpful option, if your grandmother finds it too hard and needs help. I know it's physically and mentally exhausting being a care giver.
Again, I am so sorry. Thinking about you and your family.