Answer
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
The Fidyah is not valid if given prior to the month of Ramadan, since fasting is prescribed for being present during the month of Ramadan.
Answering your question, the European Council for Fatwa and Research, states:
In the case of having a chronic disease, one should give the Fidyah (ransom) of feeding one poor person per day. Allah says: {For those who can do it (With hardship), is a ransom, the feeding of one that is indigent.} (Al-Baqarah 2:184)
According to the Hanafi School, it is valid to pay Fidyah for the entire month of Ramadan on the first day of Ramadan.
Ibn Abdeen (may Allah be pleased with him) says:
“An elderly person unable to observe fasting has the concession to break fasting and in return they give the prescribed ransom even on the commencement of the month i.e. s/he has the option of giving it at the beginning or the end of the month.” (Al-Dur Al-Mukhtar and Hashiyat Ibn Abdeen vol. 2, p. 427)
The Fidyah is not valid if given prior to the month of Ramadan, since fasting is prescribed for being present during the month of Ramadan. Allah says: {So every one of you who is present during that month should spend it in fasting.} (Al-Baqarah 2:185)
Incapability is not recognized until the prescription becomes due and no performance is done prior to prescription. Establishing a link between Fidyah and Zakah is invalid, since Zakah is valid if paid prior to its due term since the prescription of Zakah is dependent on the ownership of a given minimum. Once one owns the minimum amount, one could pay Zakah before its due term, whereas paying Zakah before owning the minimum amount is invalid.
Almighty Allah knows best.
Source: https://www.e-cfr.org/