This funny guy at a whiteboard explains "quantum immortality" in a way that is entertaining. He concludes that death without cryonics leads to an existence with less "specificity". I think his point is well taken but I would add that it's quite possible that a mind in quantum-foam MIGHT be able to maintain specificity through sheer willpower alone as we see in NDE's, Near Death Experiences. Further, another meat-body could produce the focus needed for a quantum-mind to again have specificity.

https://m.youtube.com/watch?v=4Uz6anwm47g