They can seek out the McDonalds that was in the "dream state" and if they find the cashier with the dragon necklace, they have PROOF POSITIVE evidence that their mind extrapolated real information around them without being physically present to it.
Now, the person KNOWS that what they experienced was BEYOND illusion or imagination as they have proof. However, this doesn't prove the existence of a spirit realm, but it does provide evidence towards that understanding of existence. Like finding an organic sample in the forest of an unknown creature. The evidence suggests a creature, but the specifics are sketchy. However, drawing a conclusion that there is no creature at all would be unscientific because that's ignoring evidence, it's essentially bias.
So many of your PROOF POSITIVE evidences are not that at all. How specific was the description of the dragon necklace? Why do you have to seek out a McDonald's restaurant that has a cashier wearing one? How many do you go to before you can give up? If I find a dragon necklace on the cashier's neck in the ChinaTown McDonald's, you declare an out-of-body experience because of such a coincidence? NONSENSE.
Now, if Sabastious woke up from his near-death experience and said that he noticed the receptionist for the hospital on his way out the door during his out-of-body experience, and said her nametag said "Shelia" and she was wearing a "green and gold" dragon necklace breathing fire into her cleavage, then you would have sufficiently taken on as much coincidence as possible (providing you didn't already know that Shelia worked there).
Really, all you have to do is apply the same standards of requirements that you apply to rejecting valid evidence of scientific reasons for things and you will reject this kind of nonsense. "Seek out the McDonalds" ! Balderdash!