It is very difficult to provide water tight evidence for life after death since near-death experiences are subjective and do not provide objective proof.
The situation changes if one has a testable theory of consciousness. The theory of consciousness presented here is inspired by Topological Geometrodynamics (TGD). TGD was born as a proposal for a unification of fundamental interactions, and indeed provides a general theory of consciousness as a generalization of quantum measurement theory predicting that consciousness, life and death are universal phenomena. The theory relies on new views of space-time and classical fields, and provides a new ontology behind quantum theory that predicts that state function reduction involves time reversal.
The proposed hypothesis forces a new view of the relationship between experienced time and physicist's time, and generalizes thermodynamics so that the second law is replaced with what I call the Negentropy Maximization Principle. Also cognition is included and forces the extension of real number based physics to adelic physics including not only reals but also p-adic number fields. Adelic physics predicts a hierarchy of phases of ordinary matter with a non-standard value heff of the Planck constant interpreted as dark matter which for large values heff is quantum coherent at arbitrarily long scales. Theory makes testable predictions at all scales supporting the proposed view of the continuation of life beyond biological death. A model for what happens in biological death and an explanation for various aspects of near-death experiences emerges.
For a summary of earlier postings see Latest progress in TGD.