Manava Dharmashastra 3.222

3.222

svādhyāyo vedaḥ | manvādigranthā dharmaśāstrāṇi | ākhyānāni sauparṇamaitrāvaruṇādīni bāhvṛcye paṭhyante | itihāsā mahābhāratādayaḥ | purāṇāni vyāsādipraṇītāni sṛṣṭyādivarṇanarūpāṇi | khilāni śrīsūktamahānāmnikādīni |

Manu has declared that either the grandfather may eat at that Śrāddha, or the man himself may, according to his will, perform it, after being permitted by him.—(222)

Medhātithi’s commentary (manubhāṣya):
Just as the living father is fed, so is the grandfather also.

Having sought permission from the grandfather, the man himself may perform the śrāddha; i.e., he should make the offering to the two remoter ancestors, or to the great-grandfather only. This is what is implied by the terms ‘may’ and ‘according to his will.’—(222)

The first half of this verse is quoted without comment in Madanapārijāta (p. 542);—also in Nirṇayasindhu (p. 362);—and in Śrāddhakriyākaumudī (p. 554), which notes that ‘Śrāddham’ stands for the ‘Śrāddha-oflferings,’ the things offered; as the ‘Śrāddha’ itself cannot be eaten, the meaning is that the living grandfather should be fed on the substances offered at the Śrāddhas, and then the offerings made to the dead Father and Great-grandfather.

Comparative notes by various authors
Viṣṇu (quoted by Kullūka).—‘Or, he shall perform two Śrāddhas—to the father and to the grand-father.’