I recently read on the Cole's Foundation website as Cole's father described how seeing his child suffer helped him for the first time to really understand what God the Father went through for our salvation. He had the power, the ability to instantly stop the suffering of His Son, Jesus Christ, yet he didn't. He watched His Son suffer for people who didn't even deserve it - us, sinners, not even innocent. I think when you lose a child, whether you have to watch them suffer or not, you understand to a degree how much God the Father loves us. It is humbling and amazing to realize that we love Him because He first loved us.
May your grief lead you to a closer relationship to the One who holds the keys to heaven. May you one day be reunited forever in heaven with your beloved child!