Steve Daily is all that the source you cited said that he was. IOW, he was once a major SDA pastor.
From my graduate background in psychology, I am hesitant to make a diagnosis absent an in-depth personal interview with the individual. IOW, I do not like to do such for any historical figure that has lived in the past.
My initial evaluation of this book is to consider it to be somewhat in the same light as I have considered the book written by Walter Rae: The White Lie. I consider the SDA Church to be endebted to the work that Rae did. He discovered facts. I do not argue facts that he discovered. However, I faulted him for his evaluation of facts. I had followed Walter Rae for years, while he remained a "good" but extreme Adventist. I faulted him at that time because he elevated EGW well above the position that she should have held. Then when he found her to be human, facts that could not be dismissed, he changed his opinion of her 180 degrees and went totally in the exact opposite direction.
I believe that Steve Daily would have been more helpful if he had been a bit more nuanced in his evaluation of EGW. For whatever reason, I think that he has gone further than warrented in his evaluation of EGW.