Quantum Mechanics shows there's life after death

No problem can be solved from the same level of consciousness that created it.”
Albert Einstein
applies here perfectly

Quantum Mechanics does not "show" there's life after death. It "explains" how it could happen. This explanation is not a proof, it is a metaphysical theory that cannot be confirmed by science because it goes beyond our empirical capabilities.

Humans have a tendency to try to explain unexplainable phenomena with other unexplainable phenomena, thinking that putting two unexplainables together will result in a sufficient explanation. We can't know what it is like to die, and we haven't the slightest idea why subatomic particles are probabilistic in nature. You can try to explain death using Quantum Mechanics, but due to our lack of understanding of how and why QM works, it can never be a sufficient explanation for what happens after death.

So what you're saying, is you can't get knocked unconscious because you wouldn't be able to experience that state? I'm not looking forward to my upcoming surgery then.

BTW, you can only be in superposition from someone else's point of view, not from your own point of view. So while you may be alive in an alternate history, the dead version of you has no connection with that history.