[In response to: "Christians, my unsaved grandmother passed away. I'm scared she is burning alive in hell. What can I do to help her? I'm 14."]

You can do nothing for her. What you can do is always seek God the Father through His Son, Jesus, to be your Lord and Savior.

Read about Lazarus and the rich man in Luke.
Luke 16:20 At his gate was laid a beggar named Lazarus, covered with sores
Luke 16:21 and longing to eat what fell from the rich man’s table. Even the dogs came and licked his sores.
Luke 16:22 “The time came when the beggar died and the angels carried him to Abraham’s side. The rich man also died and was buried.
Luke 16:23 In hell, where he was in torment, he looked up and saw Abraham far away, with Lazarus by his side.
Luke 16:24 So he called to him, ‘Father Abraham, have pity on me and send Lazarus to dip the tip of his finger in water and cool my tongue, because I am in agony in this fire.’
Luke 16:25 “But Abraham replied, ‘Son, remember that in your lifetime you received your good things, while Lazarus received bad things, but now he is comforted here and you are in agony.
Luke 16:26 And besides all this, between us and you a great chasm has been fixed, so that those who want to go from here to you cannot, nor can anyone cross over from there to us.’
Luke 16:27 “He answered, ‘Then I beg you, father, send Lazarus to my father’s house,
Luke 16:28 for I have five brothers. Let him warn them, so that they will not also come to this place of torment.’
Luke 16:29 “Abraham replied, ‘They have Moses and the Prophets; let them listen to them.’
Luke 16:30 “ ‘No, father Abraham,’ he said, ‘but if someone from the dead goes to them, they will repent.’
Luke 16:31 “He said to him, ‘If they do not listen to Moses and the Prophets, they will not be convinced even if someone rises from the dead.’ ” NIV

I am sorry your grandmother was unsaved. I know many that passed away that I am afraid are in the same situation.

May God Guide You and Comfort You and Strengthen You Always

God Bless