He must recommend a fidya, which is to feed a poor person for each day; because the making up was obligatory upon him and he became unable to fulfill it due to his own negligence, so the obligation shifts to its substitute, which is the fidya. See: Al-Hadiyah Al-Alaiyyah p. 173, and Bada'i Al-Sana'i 2: 104; It was narrated by 'Amrah bint Abdul Rahman, who said to Aisha (may Allah be pleased with her): My mother passed away and she had to fast Ramadan, is it permissible for me to fast on her behalf? She said: No, but it is better to give charity on her behalf for each day to a poor person than your fasting. Ahmad Al-Tahanawi mentioned in I'la Al-Sunan 9: 155: It was narrated by Al-Tahawi, and this is a good chain as mentioned in Al-Jawhar Al-Naqi 1: 210. And from Ibn Abbas (may Allah be pleased with them), he said: No one prays for another nor fasts for another, but he should feed a mud of wheat for each day instead, in Sunan Al-Nasa'i 2: 175. Ibn Hajar said in Takhlees Al-Habeer 2: 209: Its chain is authentic. And from Ibn Umar (may Allah be pleased with them), he said: No one prays for another, nor fasts for another, but if you wish to do something, then give charity on his behalf, in Musannaf Abdul Razzaq 9: 61. Al-Tahanawi mentioned in I'la Al-Sunan 9: 155: And its narrators are the narrators of the authentic hadith except for Abdullah, for he is from the narrators of Muslim and the four (books), and there is a difference of opinion regarding him.