In my opinion this is to state thing too severely. We all know what happens to a dead animal after a few days or weeks, the whole thing simply rots and decays. If we are talking about returning from the dead, there has to be some quantity of reasonableness allowed, otherwise, all one is doing is setting unreasonable conditions, and then declaring "I knew it was impossible".The point is that no one has ever really returned from death, these are people who were saved at the last minute and who had cardiorespiratory arrests or very long surgery, trauma and states of coma and near death that lasted even an hour or more. no one has ever been brought back to life within days or weeks of death by current resuscitation techniques, which are useless if they are not performed promptly.
In real-life cases, there have been people dead for 18 hours or maybe longer. And then, by modern techniques, brought back to life. That seems to me to be more than long enough to fit any reasonable expectation. Here's a case of being brought back to life after six hours. That is pretty astonishing, I think we have become very casual and unexcited by what would in previous centuries been sufficient to declare a miracle:
Briton Audrey Schoeman revived after six-hour cardiac arrest
video: The woman brought back to life after her heart stopped for six hours
Incidently, that was reported by the BBC, who were probably happy to do so given that the woman concerned had no memory of those six hours. In the past, the BBC was more broad-minded, but these days they tend to regard any mention of surviving death as mere belief, rather than (possible) scientific fact. However here's a BBC documentary on reincarnation from 1992:
BBC on Remembered Previous Lives