Don't recall saying he was possessed...I think you misread.I've got Secret Histories. I'll pass on the video. Well researched or not... He did more for Christendom than you or I could ever imagine doing.
I'm not gonna derail the thread anymore, but seriously consider the impact of calling someone whom is a Saint possessed by demons. Considering this is an Orthodox forum, I'd be more careful with your language... but that's your call.