How to make up the fasts she missed after fasting for several years and becoming advanced in age

The questioner:
May Allah reward you with good and do you well. Our sister says: My mother is an old woman, over sixty years old. She says that she missed approximately three Ramadans, meaning three months, about thirty years ago, at the time of her childbirth. Does she have to make them up? And if making them up is difficult for her, what should she do? Knowing that she was ignorant, and she says that the one who missed a Ramadan would give charity, and they believed that it suffices in place of fasting. Please guide us, may Allah reward you with good.

The Shaykh:
It is obligatory for her to make up the months she did not fast. Yes. Her obligation to make them up does not drop as long as she is capable of doing so. As for the fact that making them up is difficult for her, she can spread out the making up according to her ability. She is not required to make them up consecutively until she finishes; rather, it is permissible for her to spread them out according to her ability and means until she finishes them. In addition to making them up, she must feed one poor person for each day as expiation for the delay in making up the fasts until this time. Yes.

The presenter:
May Allah reward you with good. Since she is advanced in a certain age, Shaykh, do you have any other guidance?

The Shaykh:
If she has become so old that it prevents her from having strength? If she is very old and cannot make up the fasts, feeding is sufficient. She feeds one poor person for each day.