Do you believe that there are dead people currently alive in heaven?
What does the Old Testament say?
Ecclesiastes 9:5
For the living know that they will die, but the dead know nothing; they have no further reward, and even their name is forgotten.
Job 14:14
If someone dies, will they live again? All the days of my hard service I will wait for my renewal to come.
The writers both knew that they had to wait to be resurrected. They were not going to heaven at the point of death.
What did Jesus say in the New Testament?
John 3:12
No one has ever gone into heaven except the one who came from heaven — the Son of Man. (NIV)
If no one had ascended to heaven when Jesus was alive, then there is no reason to think that anyone has done so since.
What did Peter say?
Acts 2:29-35
“Fellow Israelites, I can tell you confidently that the patriarch David died and was buried, and his tomb is here to this day. But he was a prophet and knew that God had promised him on oath that he would place one of his descendants on his throne. Seeing what was to come, he spoke of the resurrection of the Messiah, that he was not abandoned to the realm of the dead, nor did his body see decay. God has raised this Jesus to life, and we are all witnesses of it. Exalted to the right hand of God, he has received from the Father the promised Holy Spirit and has poured out what you now see and hear. For David did not ascend to heaven, and yet he said, “‘The Lord said to my Lord: “Sit at my right hand until I make your enemies a footstool for your feet.”’