Agree +1. I didn't see anything about the niece and what she wants. Other plausible reasons are she isn't showing a strong interest in the schools and/or is raising red flags about her desire to play.She get lots of looks because she is 6'4". Perhaps the interview draws the flag hmmm
My advice-don't get involved in niece's affairs, in the long run it may affect family dynamics
I also advise being very cautious about getting involved. If you do, make sure you know what the niece really wants first so you can advocate on her behalf. Her TB coach probably knows why the college coaches are moving on.
A lot has been posted about the parents and they certainly raise red flags. Beyond their direct involvement with some schools, most coaches do their homework on the parents and monitor them while watching games.