Aww, Sundae. That sort of thing is hard on the family, but everyone will pull together. I've only seen my great niece in real life once (she's just now starting to crawl) because they live far away but I will be seeing her more in the coming months.
For us, since we'll never be grandparents, we get the joy of being great aunts. I expect you'll regale us with stories of the twins' shenanigans, or I hope so anyway.
Don't sweat the other stuff.
edit: I'm a bit disconcerted about your grandpa's stuff though. That seems a bit...shitty. I'm sorry, hon.