Could Someone Go to Hell Because No One Prayed for Him?

It is true that God wills our prayers to be a cause of good, including the administration of grace. And such grace can help someone attain heaven.

But this doesn’t mean that if someone ends up in hell it’s simply because no one prayed for him. 

Anyone who ends up in hell will be there due to their rejection of God’s grace, which Paul says is sufficient for all to be saved (2 Cor. 12:9). The Catechism of the Catholic Church (CCC) states, “God predestines no one to go to hell; for this, a willful turning away from God (a mortal sin) is necessary, and persistence in it until the end” (1037).