Observation and existence and world of nothingness?

In physicist John Wheeler's universe, nothing exists until it is observed. He had carried out a number of experiments that led him to his conclusions. It is part of his Participatory Universe theory.

From another perspective, people who experienced near death came back to tell of different worlds each one of them had encountered. Some people who were highly dissatisfied with their lives went to a world where they claimed to see thugs that beat them up.

Some people who were humble and honest went to a beautiful garden and they felt extreme peace or they might even be greeted by deceased relatives who told them it was not their time yet. Some just went to a world of nothingness. Everyone of them could also attest that time did not exist there. When they had gone over there, they had felt it was like it was only a while ago they had been there.

From all these perspectives, it would seem what one experienced over there were unreal and only made to be, very much like the holodeck aboard the Enterprise.

Do you think there is a link between all these and John Wheeler's Participatory Universe? That is, nothing really exist out there until you witness it?