If someone reaches Ramadan while having fasts to make up for from the previous Ramadan which could not be made up due to excusable circumstances, what should be done to make up for the (missed) fasts

بسم الله الرحمن الرحيم ، الحمد لله رب العالمين، و الصلاة و السلام على رسول الله – صلوات الله و سلامه عليه- وعلى آله و صحبه أجمعين.

أما بعد:

With regards to the question about fasting, there are two instances because of which a person may delay fasting

The first instance

To delay fasting due to negligence and carelessness. Since the circumstance mentioned in the question does not fall under this category, the second instance will be mentioned

The second instance
When Ramadan is met while there are missed fasts from the previous Ramadan not made up for due to excusable circumstances. For example, missing fasts due to being unwell from pregnancy during the previous Ramadan and the next Ramadan approached while she could not make up the missed fasts due to breastfeeding. Or she was faced with an illness that prevented her (from making up the missed fasts). In this case, she makes up the missed fasts once she recovers from her illness. There is no other ruling upon her. The evidence for this is
(فَمَنْ كَانَ مِنْكُمْ مَرِيضًا أَوْ عَلَى سَفَرٍ فَعِدَّةٌ مِنْ أَيَّامٍ أُخَر)
”..if any of you is ill or on a journey, the same number (should be made up) from other days.“ (2:184)

Some additional information regarding this
It may be an incurable illness confirmed by doctors. Meaning, the person will not have the ability to fast. In this case the person has to feed a Miskeen for each (missed) fast. If it is rice, 1.5kg of rice for each fast to be given to a Miskeen

والله تعالى أعلم. وصلى الله على نبينا محمد وآله وصحبه وسلم.