Yes, he must obtain prior written permission (or a No Objection Certificate/NOC) from his department before enrolling or appearing for examinations. Submitting the degree certificate after completing the course without prior approval is not sufficient and violates government conduct rules.
Central and State Conduct Rules mandate that a government employee must inform their appointing authority and obtain explicit permission before pursuing higher studies or appearing in any board/university examinations.
Pursuing a degree secretly or without formal permission constitutes misconduct, which can lead to administrative or disciplinary action against the employee. The qualification will not be added to his official Service Book unless it was completed with prior department approval. Unapproved degrees cannot be used for claiming departmental promotions, higher grade pay, or incentives.