Doctory (Pastor) Arnold Murray said in his lectures that when we're in heaven, the Father will make it so that we'll have no recollection of that person, as they're placed far from God by their own choice in life. We'll be able to praise God Almighty with joy in our hearts, never thinking about the sufferings of those we loved on earth, it'll be like they never existed to us.
On the flip side, those in great torment below will have constant memories of loved ones.
Pray that your grandfather will be saved! God will help you, IHL. God is so full of mercy that it's hard for Him to understand how we ourselves can't be merciful. He loves us so much, He sent Christ to die for our sins. Share that with Grandpa, share Christ!
