Is it permissible to pay the expiation all at once?

Question: Two years ago, my mother was struck by a severe illness, which forced her to take medication prescribed by her treating physician. He advised her not to fast, but she fasted without his knowledge, became exhausted, and left off fasting for twenty days. Now that her health has improved, she feels she is able to fast. She was told that she must pay an expiation in addition to making up the fasts because she delayed making them up. Is it permissible for her to pay the expiation all at once and fast, or must she pay it day by day? What is the amount of this expiation, given that her mother was able to fast (make up the fasts) within a certain period due to her improved health, and she fasted the entire month last year? May Allah reward you with good, and benefit us and you with the Noble Qur'an.

Answer: Your mother is only required to make up the fasts if she is able to do so, and she is not required to feed the poor if her delay in making up the fasts was due to illness until another Ramadan arrived. However, if she delayed it out of negligence, she must feed one poor person for each day in addition to making up the fasts. The amount is half a sa' of the staple food of the country, such as dates, rice, or something else, which is approximately one and a half kilograms by weight. It is sufficient to give the entire amount to one poor person. May Allah guide everyone to understanding in the religion and steadfastness upon the truth, for He is the All-Hearing, the Near.