Revelation – interpretation or fact.

Hello and thanks in advance.
My Moroccan mother-in-law occasionally tells me that her late husband appears to her in a dream.
I also once dreamed about my grandmother who passed away.
The difference between us is the interpretation.
The fact is that we both saw someone die in a dream, she calls it a revelation to her and I prefer to stick with the dry fact that I simply dreamed about someone.
 
When a prophet says that God revealed himself to him, how do we know that this is not his personal interpretation? That is, even assuming that I believe him and don't think he is lying, he experienced some special experience, but how do we know that his interpretation of the experience is the correct interpretation?
Especially when we have no ability to check and criticize his interpretation, because it is his personal experience in which we have no say.