Is there some way we could get the man to respond himself? If anyone reading this is his student, please ask him.
His student David Chapman runs the site http://approachingaro.org
, a site the defends this lama from his critics. You can read their perspective there, and ask them anything you want. I did that years ago, asking clarifying questions to David and also discussing him with the close disciples of the lamas he was a past disciple of, and people who have had a close relationship in the past. I'm not bringing up anything about contested facts here... other than whether or not he would say behind closed doors that he is a terton. I'm just going on hearsay here... although thinking back on it it might have been David who told me that, I can't quite remember.
I have never heard the slightest thing about Ngakpa Chogyam having any negative conduct towards his students. He does promote good conduct and his students show those qualities as well. Many of them have been loyal to him for 15 or more years, and that says a lot.