So you know more than God has revealed in His Word through King David and the Porphet?
Here is biblical proof about the death of infants. In 2 Samuel 12 we learn of David’s affair with Bathsheba, another man’s wife. David was informed by the prophet Nathan that the child produced by that union would die.
David then began to fast and pray, asking the Lord to not carry out His judgment. When the child did die, David got up from praying and fasting and ate something.
When asked about this behavior, David uttered the words recorded in 2 Samuel 12:23;
Verse “Now he is dead; why should I fast? Can I bring him back again? I shall go to him, but he shall not return to me.”
David’s words reflect a clear understanding that the child could not come back to earth, but David would be with his child one day in heaven.
This indicates not only David’s assurance of his own future in heaven; Psalm 23:6, "Surely goodness and mercy shall follow me all the days of my life: and I will dwell in the house of the LORD for ever," but also the assurance that his child would share that future. From this account, we can conclude that infants who die are destined for heaven.