After my grandfather's death I had no idea what to do.
I am sorry to hear about your loss. Do you want to talk more about this?
My father wanted me to talk about my grandfather, but I didn't know what to say.
I'm sorry for your loss, and people grieve in different ways. This is your own way of mourning, and the best you can do is just be there for your father and the rest of your family until things get better.
Is it true that everyone my grandfather knew were all waiting for him to kick the bucket?
I doubt that was true and I think your emotions are getting the better of you. It is expected to need support from a group or professional when you have a loss like this.