How do we know if a deceased person is in heaven?

According to the Scripture, if a person dies having a relationship with Jesus Christ, he or she is guaranteed to go to heaven. However, we are not here to judge the dead person as to whether he or she is in heaven or not, because only the Lord knows each person's heart. What we can do is trust that the Lord has given everyone the opportunity to know Him. God desires for all people to be saved. So we can be confident that the Lord has given every person an opportunity to know Him. We can only pray for his surviving family; we cannot pray for the deceased because death brings quick judgment. The author of Hebrews states, "And just as it is appointed for man to die once, and after that comes judgment" (Heb. 9:27). Unfortunately, anyone who does not put their trust in Jesus Christ will be condemned to eternal damnation immediately after his death. According to the Lord Jesus, "Whoever believes in him is not condemned, but whoever does not believe is condemned already, because he has not believed in the name of the only Son of God" (John 3:18). This is why we need to have a personal relationship with Jesus Christ.