Either way, there's no reason that this ~shouldn't~ affect you... so while I can't make the pain go away, I just hope you realize that how you feel is normal. And that at night, when yuo're by yourself, you just want to let it all go? Then let it go... It's hard to face the reality of the situation, but with time, you'll find that you're able to start coping with it... and instead of sadness when you think about him, you'll remember the good times you spent with him. That's what I believe anyway.
My condolences to your and your family.
I've never suffered a severe family bereavement ,I couldn't give solid advice, although what I hear most of time is accept it and move on. - Which i'm sure would be difficult at first.
I'm not sure about the ways to cope though, just...be glad that you are still young and healthy and so's your family.
And Cool, my great-grandfather passed away at 97 too. Technically it's 101, but somehow after calculations it was 97.