I can say that he has endlessly promotes martial arts and mantis.
I was able to personally meet and talk to him at the Great Lakes Kung Fu Tourn. in Cleveland Ohio few years ago when I showed for masters demo with my Sufhu. He lacks any humor and was incredibly stand-offish with anyone that didn't bow and grovel when talking to him or give him the complete attention of every word he said. This is personal experience but I do not give any leeway to arrogance and position of power.
Anyone can die or be beaten, so don't be a snot about your status and skills. Unfortunatly most "masters" and instructors don't realize this and are very deluded about themselves and how the world revolves around their opinion.
That's personal opinion but almost everyone that was there saw his reaction when I basically explained this to him after he got nasty with me for being realxed during the masters discussion when we were all discussing rules and such for the tournament, which I judged in.
All this points to how be handles himself with interpersnal relationships and his ego but this is one teacher's opinion as a warning in how he behaves. He could be nicer or more relaxed now, but I don't see teachers changing that much when they can support and keep stablized the environment that promotes such ego. He might be an incredible teacher, that is a fact, but I never learn from people that corrupt their teaching message with ego also. Just personal philisophical choice and reasoning. Maybe you should try it though for yourself as any chance to learn is good but just remember others experiecnes and keep it in the back of your mind.

I hope everything works for the best and my experienes are not repeated with anyone else. It is terrible to meet old school promoters you grew up seeing and respecting as martial arts images of why you got involved and then they are totally oposite of what the arts are supposed to promote.