Ash:
I am so sorry to hear about your grandfather's empending passing. I can tell you what helped me cope when my father passed away 29 years ago. Ask for a memento, something that meant a lot to him. Having that item close and holding it helps.
My father was in his fifties when I was born so he was more like a grandfather to me. He used to put me on his lap when I was a small child and play his harmonica for me. I absolutely loved it. I asked for that harmonica when he died and it is my greatest treasure. When I hold that harmonica I feel like a part of him is still with me.
Target