I have, and it breaks my heart. I have a friend whose uncle was sucked in to it. He was mostly apolitical and it was a bit surprising when he started talking about it. Last I heard he was convinced a coup would happen on January 20th and Donald Trump would be declared the 17th president of the Restored United States. It has definitely taken a toll on his psyche.
You might want to have your Uncle read some of the basic books on NLP (see my prior post).
Once he understands the techniques that were used on him, he will feel better about himself and realize why he was duped.
Some folks are more susceptible than others to this type of brainwashing—not their fault.