First off, I am glad to see you return, you were well missed.
Secondly, I have the utmost sympathy for your situation and I feel deeply for what you, your grandmother, and your whole family have gone through. I have had similar but less drastic incidences of this type of situation occur in the past and its one of the things I dread most of anything. My family is very very close and it would just tear us up to lose anyone. I'm getting quite sad even thinking about it...
I really truly hope your grandmother and the rest of your family can find peace with what has happened. I am sure your grandfather would not have wanted to leave everyone in such a state on his behalf. Its my belief that remembering the best times and holding them close is what counts and its also what I would hope my family would do for me.
Again, welcome back bro. I hope the best for you and your family and don't place us on too high of importance right now man, your family comes first so take your time.