Secondly, what is objectively unverifiable about a man back from the dead?
That something must be objectively verifiable is a necessary condition, but not a sufficient one. Sufficiency requires that it is objectively verified.
Now it is certainly reasonable to suggest that it is objectively possible to verify that a person is clinically alive, then that the person is clinically dead, and then after three days is clinically alive again. All of those assessments are possible using objective methods.
But that isn't sufficient - for the evidence to actually be credible you need sufficiency - in other words that you have objectively verified that the person was clinically alive, then clinically dead for three days and then clinically alive again. That's where the credibility falls down. Firstly because it has, obviously, not been objectively verified as all we have are decades-later assertions with no objective verification. But further, although theoretically objectively verifiable, the notion is completely implausible given our understanding of human physiology as there would have been permanent and irreparable brain (and other tissue) damage in that three day period.