At some point we have to redound to best credible information. Otherwise, anyone anywhere in the world could say(as an example)- “60 years ago my mother and father flew from china to the U.S. , got emergency citizenship just before I was born, and then flew back to Shanghai before anyone even knew we had left.. Prove otherwise.”
There is no credible information and the person in question absolute refuses to comply with common practice. He can not be trusted.