Not a fantasy, it's Quantumonics.

1. Afterlife is no fantasy because quantum reality is no fantasy. Before you label afterlife a fantasy, you would have to state your position on quantum physics and demonstrate an understanding of 10*-23 to 10*-43. I would point to Doug Matzke in Deep Reality. [2018].

2. Quantum-afterlife has a better chance of housing our personality and memory than any STEMG-dimensional existence *SpacetimeEnergyMatterGravity
All STEMG structures are eventually subject to destruction and that's why framing our immortal personal existence as quantum-souls as a backup system is better than any STEMG structure.

3. By definition, the quantum-deep-reality can't break down any further than it already is. It's the very definition of non-existence as well as existence. Again, see Matzke. It is so elemental that even time and space don't exist. The destruction of the soul is theoretically possible but I think that would be up the Source, God. Unless you can concieve God committing suicide, then our souls are safe. Cryonicists have failed to grasp deep quantum reality.

4. Casper would be, by definition, entirely housed in the quantum realm like all souls but instead of fully manifesting as a reincarnated STEMG being, he would be phasing in and out of STEMG reality and confined to one house. The ghost, as quantum soul, requires an object to "anchor". In Casper's case, I'd have to reread the comic books to see how far he goes from his original house and town. Not far I don't think. Once the sun supernovas, Casper would retreat to quantum-deep-reality like the rest of us and wait for planets to coalesce again for another reanimation in STEMG reality.

5. Were all ghosts in the brain machine. There is no "us" "in" the machine-brain just as there is no "Tucker Carleson" in my TV set. The brain is an antenna that 'anchors' the quantum-transmission. The brain learns through experience and uploads those learning-experiences to the quantum-self, the ghost, the soul. Our bodies are avatars of the perpetual soul that is us as individuals.

And that's Quantumonics. It solves everything.