Reference: Fataawa Ramadhaan – Volume 2, Pages 661-662, Fatwa No.667
Fataawa al-Lajnah ad-Daa.imah lil-Buhooth al-‘Ilmiyyah wal-Iftaa. – Fatwa No.6422
Question: A man has fasts from Ramadhaan to make up, [so] is it permissible for him to split the fasts up [rather than fast them all consecutively]?
Response: Yes, it is permissible for him to make up that which is required of him by splitting them up over a number of days, due to the saying of Allaah (Subhaanahu wa Ta’aala):
…and He (Subhaanahu wa Ta’aala) did not stipulate for them to be made up consecutively.
And with Allaah lies all the success, and may Allaah send prayers and salutations upon our Prophet Muhammad ﷺ and his family and his companions.