Well, there are some constraints regarding conditions in any possible parallel universes.
This universe we live in was formed with some very narrow indices. Some cosmologist believe if any of just 6 natural parametyers were to be changed by a couple of percentage points, we wouldn't be here today.
That leads to the problem that there is no guarantee parallel universes have values anywhere near what our universe contains.
For me the question is even more basic.
What constitutes self-awareness.
Obviously, our brains need to be functioning to be self-aware. We perceive our universe with a set of eyes, ears and other internal and external sensors.
Our brains sort and filter all this information and even distort it to meet our expectations. Such is the nature of photography.
Our brains automatically make adjustments to keep light we expect to be white, look white, even though it has a decided orange (tungsten) or green (flourescent) tinge.
As it is we only 'see' a very, very small slice of the electromagnetic spectrum. There is a lot more of our universe we cannot internally detect.
We know there is a realm much smaller than we can perceive, that doesn't work, physically, the way we expect but we are able to calculate and understand how that part of our universe works
When we die, so does our brain. What mechanism could perpetuate the sense of self-awareness. How would we see, hear and perceive in an afterlife?
That question begs another.
If self-awareness continues after death? How come we have no self-awareness from before birth?