I don't want my Grandad to die..?

I'm really sorry to hear about your grandma. As to coping with change, I don't know, it's tough. I lost my grandpa and grandma on my dads side when I was a teenager and it hurt like hell. Then about 12 years ago lost my dad to cancer. I do have one thing I can tell you, I heard this some time ago, I think it was on the radio. That people will sometimes say you will get over it. They mean well but they are wrong. You don't get over it. But you do get used to it. I think the pain somehow becomes a part of you, and it helps you to understand what other people are feeling. Sounds crazy but it's been true for me.