Many people can tell (and told) what happened around them during their experiences.
For example the EXACT discussions of the doctors around them.
These experiences can't be hallucinations.
Some people are even heard the thoughts and felt the fellings of others.
Going as far as feeling the feelings that they caused to them during their earthly lives.
Some people are even met relatives that they did not met (and they did not know) during/in their earthly lives.
Not to mention the fact that many people are feeling these experiences more real than the so called real world, and they remember their experiences decades later, as if their experiences would have happened yesterday.