The Yeshivot and Kollelim struggle for funds and if a student is there just filling a seat, they won't allow him to stay. Either you learn or you're out. Token gestures aren't accepted or tolerated. Usually, there are waiting lists, especially for Kollel bachurim, so they won't tolerate a slacker.
My nephew is at Yeshivat Moshe..it's a smaller Yeshiva with limited capacity and a waiting list a mile long. The level of commitment required, is incredible.
I know the majority of kollel students are sincere and dedicated. Unfortunately, there are a few who give the institution a bad name.
I say yasher koach to your nephew. It's Torah learning that keeps the nation alive.