The simple answer is usually the right answer

It is very clear that many of those with a scientific bent are prepared to twist themselves into knots and 'nots' in order to find some way of explaining this world from the current scientific paradigm, hence theories about multiple worlds and parallel universes.

Applying Occam's Razor, one suspects that it is all far simpler than science or religions have theorised. Things generally are.

Many spiritual teachings posit that we are spiritual beings, i.e. we have a 'body' which operates at a higher, non-material frequency and the mind and consciousness inherent in that soul or self, incarnates in this world, in material form. NDE's and OBE's suggest that it is possible for the astral body to 'exit' the material body, while remaining linked so return is possible, and function in other non-material dimensions.

And given that death comes to all of us, at different ages, stages and levels of intelligence, why would not death be no more than the 'astral' or spiritual 'self' exiting the body once and for all and continuing on in it's natural dimension, i.e. home. This material world being no more than an experiment in which each of us has chosen to participate, at least once and perhaps for some, many times?

As Above, So Below. As Within, so Without. The constant is 'mind' which can and does operate through a material brain partially, but not completely and which, when released from the confines and limitation of material brain function, returns to its true and greater self.

If a child or cretin can die then neither material consciousness or intelligence are required. This is of course based on the theory that we are more than our material selves and that we exist beyond this material world.

If we do not it is all rather irrelevant. But if we do not then this universe has no purpose or meaning and that runs counter to everything we learn about this world. Every cause has an effect; there is meaning and purpose in every action and to me that says, there is meaning and purpose in our lives, which, given the fact that they suddenly end, means there must be a greater and ongoing meaning and purpose.