My friend who is a lecturer in college is married and lives happily with her husband. She has noticed that one of the students likes her. Please help her how to tackle this student.

She has to be careful that she should not pass any affirmative signals to him, knowingly or unknowingly. At the same time ignore him in subtle way. Do not try to explain or advise him on this because that will give wrong signal that you are giving importance to him, rather be indifferent to him.