Skepticism is healthy. Making decisions based on assumptions, however, is not.
I've seen Terry and his wife and kids train (but not his class; sadly, my mother had me too scheduled in last time I was in Dallas to see more), and they've attended my class, and worked out with my sahbum, who is a VII Dan, the student of a IX Dan, who was himself a student of Gen. Choi, Hong Hi, and at one point the VP of the USTF until his integrity caused him to resign - I have no doubts about his abilities or those of his students. I say that as a member of the YomChi Taekwon-Do Association; we came from the USTF and ITF, and left when, in our opinion, the pursuit of money overcame the quest for excellence. Terry is a quality instructor, who produces quality students. The fact that he includes the Kukkiwon curriculum in his training (note that I say "includes", not "limits himself to") does not reduce the quality of his training.
I'm glad you find his teachings valuable.
I don't know you, I don't know Yomchi, so, while I appreciate your support of your friend, it does not answer my questions.