Why does father question lieutenant kotler about his father the prfessor?

Father questions Lieutenant Kotler about his father, the professor, to gauge Kotler's background and possibly to assert his own authority. He seems to be searching for a connection or a way to assert his own values, contrasting his own status with Kotler's. This interaction highlights the tension between personal history and the current political climate, illustrating how relationships and loyalties are complicated in the context of their environment.