Your pain is unimaginable and you have my best hopes. Make sure that every oppurtunity you have to spend time with your grandchild is used and fulfilled to the best of your ability so you can be grateful for the time that you had with him. I would also suggest, if you like to listen to country music, listening to Sherrie Austin's song "Streets of Heaven".
"When we go into battle, I will be the first to set foot on the field, and I will be the last to step off, and I will leave no one behind. Dead, or alive, we will all come home together." LTG Hal Moore, Jr., USA (Ret.)