Mahabharata 1.94.94

तद्दृष्ट्वा दुष्करं कर्म कृतं भीष्मेण शंतनुःस्वच्छन्दमरणं तस्मै ददौ तुष्टः पिता स्वयम्

taddṛṣṭvā duṣkaraṃ karma kṛtaṃ bhīṣmeṇa śaṃtanuḥsvacchandamaraṇaṃ tasmai dadau tuṣṭaḥ pitā svayam

Our plain-language meaning of this verse is waiting for scholar review.