Nonsense! The Jews did/do not have a concept of Christian heaven and hell. They only know a "depository of the souls," Shoel, or the Hades in Greek. David knew that he would die one day and 'go' to his son.
The real message is that David repented and humbled himself; that is the recurring theme in the Bible. God forgives those who repent. The rest is fluff for local cultural and ethnic consumption. As Nikitas Stithos (a hesychast) says, the incorruptible and imperishable are "tears of repentance, acts of charity, compassion, prayer, humility, faith, love." Those are things of God we learn through Christ.
Funny, both the Jews before and in David's day knew that God was God of the living, not of the dead. Matthew 22:32 teaches, as usual from the Old Testament, Exodus 3:6, 15, and David wrote Psalm 16:10, and Psalm 6:5.
Act 23:6-8 But perceiving that one group were Sadducees and the other Pharisees, Paul began crying out in the Council, "Brethren, I am a Pharisee, a son of Pharisees; I am on trial for the hope and resurrection of the dead!" As he said this, there occurred a dissension between the Pharisees and Sadducees, and the assembly was divided. For the Sadducees say that there is no resurrection, nor an angel, nor a spirit, but the Pharisees acknowledge them all.