When the parent loses a child they seek answers and beg to have things reversed, often rather than seeking God himself and his comfort. We are to try and look at things from His perspective, but most importantly we are to strengthen our faith in the fact that God uses all things for good, - for everyone?
No, Romans 8:28 says, for those who love Him and are called according to His purpose. We are to love him more when tragedy strikes, and we are to look for what His purpose is for us in the tragedy. Remember grief is usually selfish, it’s not about the other person, it’s about us and our pain. Of course nobody will judge us if we grieve a great loss, but God is only concerned about one thing, eternal life, our eternal life, which requires faith in God and a relationship with him. You see God doesn’t grieve the death of a child, they’re with Him, but he does grieve for the people left behind, and in his grief, he always wants us to come closer and be obedient so he can be there for us in our grief, and ultimately enjoy us in heaven.
Now this doesn’t mean that a parent who loses a child does not have enough faith. It doesn’t say that anywhere. But it does mean that at that time, he is calling them to come closer to Him so he can reveal His purpose for them. When we can look at it that way, perhaps we can see the “big picture gift” in the tragedy, and be comforted by His truth.