I know somebody who lost his 4 year old daughter due to cancer. To the best of my knowledge he is not a Christian. The daughter had numerous surgeries but her cancer was unstoppable. After her last surgery she died. Of course her father was heartbroken he wanted to die. He tried to drink himself to death and is still struggling with alcoholism. He says he doesn’t want anything to do with God because God didn’t help though he begged Him for his daughter’s life. I pray for this heartbroken father, but if he ever opens up and asks questions what can a Christian like me say to him?
As a pastor, I once found myself in a situation similar to yours. The unbelieving son and daughter-in-law of a person in our church had lost a child due to a sudden illness. After praying that the Lord would give me the words to say, I went to console them.
I told them that their child had begun her eternal life with the Lord and would now be pain free, healthy, and filled with joy forever. I showed them Paul’s statement that for those who belong to the Lord (which includes all children) to die is to gain (Phil 1:22). I also showed them the Lord’s promise that for believers the next life holds no more death or mourning or crying or pain (Rev. 21:4).
I said their daughter had been spared the dangers and disappointments of this world and the issue of her life was resolved. That left the issue of theirs. Would they decide to remain forever apart from her, or would they decide to be reunited with her and share her eternal happiness. When they asked how to be reunited, we began a discussion of the gospel and a short time later they became believers who are now grateful that their daughter is with the Lord and they know they’ll see her again soon.
You should pray for the Holy Spirit to soften the heart of this unbelieving father and draw him toward the Lord. And when he begins to ask questions, you can say something similar to what I said.
Jesus said, “In this world you will have trials. But take heart for I have overcome the world” (John 16:33).