Answer:
(Fatwa: 56/46/H=1432)
It is wajib to stop parents with wisdom and prudence i.e. efforts should be made after deep thinking in good manner at best suited time keeping in view their respect and etiquette. However, it would be better for you if you create the situation to make them convinced and advised in privacy by any influential personality.
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband
