Arthur's problem was like this. Among the civilians that lived in their campus was a branch family of theirs. They were not of the closest ties, but he cannot bear to ignore him due to their blood ties.
It is a well-known fact that children who get admitted in Ec1 Comprehensive school are not simple. There are the best of the best among their fields. And they will continue to be one as long as they survive long in the harsh standards of their school.
So the news of his admittance to their school is very spread in his family. While they are not situated in the capital, they do have people here who know about him. Leading to these said people bossing others due to him being a student of the school.