Agniveshyagrihyasutra 3.9.3.16

3.9.3.16

athāgrayaṇeṣṭipaśucāturmāsyādhvarāṇāmasamāpte vratāntarāḷe pramīyeta yadyasya putro vāntevāsī vā śeṣāṃścaikatantraṃ samāpnuyāt \

Now, if he should die during an intermediate vow before the completion of the Āgrayaṇa sacrifice, animal sacrifice, or Cāturmāsya rites, his son or pupil should complete the remaining [rites] as a single ritual procedure.