Damn Numbersguy, that's terrible. Very sorry to hear that.
The grieving process takes a while, a long while before you can start picking up the pieces and processing this mentally in a different light.
I'm sure you have known each other for some time, shared all of your dreams and fears together. You must remember what their wildest dreams were, and it's your responsibility to help bring that to fruition for them because life was taken from them. I don't know why, but for some reason I feel that if you were to accomplish that for them, you'd be reunited together again someday, somehow, somewhere.
I'll be thinking about you, I can't even put myself in your shoes, but I'm trying to and it must be a very dark place. So sorry to hear about your loss.
-Frank