Nobody is in heaven. Based on the model within Christianity, my mom is convinced that she's going to go to heaven, and that I'm going to go to hell, and I can demonstrate that mom is absolutely wrong, because in heaven there's no sadness, and my mother will always be sad that I'm in hell, which means whoever is in heaven is not actually my mom. It may be some doppelganger facsimile of my mom, but it's not my mom.