It is required to have the ability to make up the fast, even if one missed fasting Ramadan due to illness or travel and remained ill or traveling until death, he meets Allah without any obligation to make it up; because he died before the obligation to make it up was established upon him. However, if he bequeathed that food be provided for him, his will is valid even if he was not obligated, and he should be fed from one-third of his wealth; because the validity of the will does not depend on the obligation. If the sick person recovers or the traveler returns and has time equal to what he missed, he is required to make up all that he can; because he is able to make it up due to the removal of the excuse. If he did not fast until death overtook him, he must bequeath the expiation, which is to feed a poor person for each day; because the obligation to make up had been established upon him and then he became unable to do so due to his own negligence, thus the obligation transforms into its substitute, which is the expiation. Refer to: Al-Hadiyah Al-Alaiyah p. 173, and Bada'i Al-Sana'i 2: 104; It was narrated from 'Amrah bint 'Abdur-Rahman, I said to 'Aisha (may Allah be pleased with her): My mother passed away and she had fasting of Ramadan upon her, is it permissible for me to make it up for her? She said: No, but you should give charity for each day to a poor person, which is better than your fasting. Ahmad Al-Tahanawi confirmed in I'la Al-Sunan 9: 155: This was narrated by Al-Tahawi, and this chain is good 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 for each day a mudd of wheat, 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 want to do something, then give charity for him, in Musannaf Abdul Razzaq 9: 61, Al-Tahanawi said in I'la Al-Sunan 9: 155: Its narrators are the narrators of the Sahih except for Abdullah, for he is among the narrators of Muslim and the four, and there is disagreement about him.