I have a relative who has trouble sleeping. This relative also believes they hold "secret knowledge" given to them as some sort of special gift from God. In describing this scenario and a mixed up plan to change the world, they raise their voice as though I do not believe they can achieve it, even though I know better than to disagree. Over time, this relative has had major blowup events followed by peace. "I am the ONLY ONE in the world who can do this. Just wait"

Does anyone have a name for this? For a while I thought it was narcissism, and that may be part of it, but I think it has progressed to something else as well. Scary