It is not required, nor is it usually a good idea, that the instructor become concerned or involved in the students' personal lives. The indication of his excellence as a teacher is based on his students grades. In the teaching of Torah this is not enough. The Torah requires that the teacher take a parental interest in his students, and be concerned with every aspect of their lives - as though they were his own offspring. The reason for this difference is obvious.
Secular knowledge is simply a means to an end.
It is a tool to be utilized if needed, and discarded if not. How or if the student eventually uses these tools and knowledge is of little concern to his instructor. Torah knowledge, in contrast, is only the beginning of the student's ultimate goal. If the student has fully mastered the subject material of his Torah lessons, yet has failed to integrate them into his everyday life, then his instruction is far from complete. In order to fulfil his obligation, the Torah instructor must go beyond the role of teacher, and become like a father - concerned with every aspect of his students' lives.