Complex sentence: He received students, but the teacher-student relationship was kept in the most classical sense, like a parent-child relationship, in which the father carried the responsibility of the well-being, character-building and spiritual development of the child.
Split into simpler sentences: He received students, but the teacher-student relationship was kept in the classical sense. It was a parent-child relationship, in which the father carried the responsibility of the well-being, character-building and spiritual development of the child.