Question: When Lazarus died, he went to "Abraham's bosom." He "lifted up his eyes," but his body was in the grave. The thief on the cross died and went to "Paradise" with Jesus "in the heart of the earth." Christians who die go to be with Christ in heaven but won't get glorified bodies until the resurrection. In the millennium, a child will die being 100 years old and will go...where? After the millennium, the New Jerusalem descends to earth. This is not for all believers but only the church. Can you sort this out?
Response: Our spirits that separate from our bodies at death and go to be with Christ to await glorified bodies at the resurrection are not blind, deaf, and dumb until then. God, angels, Satan, and demons are all spirits and can see, think, hear, speak-and so can the human spirit, separated from its body, whether in heaven or in hell. "There is a natural [physical] body, and there is a spiritual body" (1 Cor:15:44). Such was the condition of the rich man, (conscious, in torment, seeing, speaking). Lazarus and Abraham were in the place Christ called "paradise," where He, the believing thief, and Old Testament believers went upon death.
At His resurrection, our Lord emptied paradise and took its occupants to heaven. Since then, at death, believers' souls and spirits have gone directly to be with Christ in His Father's house of many mansions (Jn:14:2). Souls and spirits of all those "who sleep in Jesus" [i.e., died in faith in Christ] are waiting in heaven for the resurrection of their bodies that will be transformed into His likeness at the Rapture.
To speak of a hundred-year-old as a "child" does not mean that person is immature physically or mentally but that to die at 100 during the Millennium would be like being cut off in childhood. Those dying that "young" must be wicked and taken instantly to hell to join the "rich man" and multitudes of others in torment.
Revelation 21 reveals the "new heaven and new earth" after the final judgment of the wicked (Rev:20:10-15). They will then all be in the Lake of Fire, not intended for mankind but "prepared for the devil and his angels" (Mat:25:41). Jews or Gentiles who believed on Christ, but not until they saw Him at the Second Coming, are not in the church but will dwell on earth eternally: in their natural bodies during the Millennium and in new bodies on the new earth with access to the new Jerusalem but not as its residents (Rev:21:24). Jews saved at the Second Coming will eternally dwell in the promised land of Israel on the new earth (Gen:17:8; 1 Chr:16:14-18; Eze:32:21-28; 39:27-29; Zec:12:10).
Jews or Gentiles who believed on Christ before His visible appearing ("blessed are they that have not seen, and yet have believed" - Jn:20:29) are the bride, the church. They inhabit the new Jerusalem, are always with Christ, and have full access through Him to the throne of God in heaven.
This is how I "sort this out." But you Bereans must search the Scriptures daily to come to your own conclusions.