Father and mother may be seen to discard the dear son if he is addicted to irregular practices. People take care of their own selves. See the efficacy of self-interest.
पुत्रं हि मातापितरौ त्यजतः पतितं प्रियम्॥ लोको रक्षति चात्मानं पश्य स्वार्थस्य सारताम्।