He has a mystical experience in which he sees "Pure White Light" and feels an "All-Embracing Love."
The opening lullaby in Frozen II is replete with mystical symbolism of all kinds, which frames the rest of the film's story.
Many mystics describe seeing a bright light in their experiences. What is that?
The answer may be found in the question, in the identification of the "I." Who we think we are and who we really are affects how we consider life after death, and what we will thus "feel" there.
The communal structure that humans evolved in is fragmenting, from large family groups, to small nuclear families, with damaging effects. We're losing mystical communion and thus community as well.
The Eastern idea of "no-self" is confusing to Westerners, but I think the same concept can be found in our Western traditions, just known by different terms.
Joseph's experiences seem to parallel those he "translated" in the Book of Mormon, perhaps indicating a deeper spiritual-mystical allegory and myth.
The experience of God is not all joy and laughter. It has often been terrifying to those who experience it. Why?
What masks do we wear? What roles do we play? What self do we think we are? It is probably not the true Self. Coming out goes deep within.
Jesus became a symbol of the "Lamb of God," the flip side of the "scapegoat" of the egoic enemy.