The closest theory to any kind of afterlife is probably quantum soul theory. I think if I recall; the belief that the brain is actually webbed into space which is a place holder for memory and information. The brain is a zero-point collective hologram where the conscious self temporarily resides. When the body dies the (?) extracts from the brain and extends back into the universe and fills the expansion volume.
Meaning that everyone is a single conscious body and when sentient lifeforms die they all converge into the once super-conscious entanglement.
Even though consciousness may be easily interpreted into the single organ that contains the super advanced thought process which makes up our consciousness, doesn't quite mean it is. We still can't define consciousness and soul is just the lazy term for it.
If this truly is the answer then that means in the quantum computer era you'll be able to download your ancestors and dead parents.
Somewhat rational Christians are now converging onto this topic trying to explain god and heaven. Their actions are predictable, this is Human nature to try to survive by adapting.
Just some cool stuff wanted to share.
Anyways, I wish it is true.
Edit: Wouldn't that create complications if we were to leave this universe? I mean if we were a property of it, then we would die.