The Noble Shaykh Muhammad Ferkūs (may Allah preserve him) was asked:

Question:
I work as a merchant in the lands of disbelief in a store that sells small meals. Is it permissible for me that I sell these meals during the day time of Ramadaan after Salātul-‘Asr knowing that from the customers there  are those who are Kuffār  and from them are those who are Muslim. May Allāh reward you with good.

Answer:
All praise is due to Allāh the lord of the creation. May the Salāh and Salām be upon the one who Allah has sent as a mercy for the creation, upon his family, companions and his brothers until the Day of Judgment.  As to what follows:

It is not permissible to cooperate with the one who fasting in Ramadān is mandated upon to begin with, like the Muslims or after the actualization of the condition of Islaam like the Kuffaar, in violating the month of Ramadān by way of eating food. That’s because it is cooperating upon sin and transgression based upon the statement of Allah:

And cooperate upon righteousness and piety and do not cooperate upon sin and transgression.

(al-Mā-idah: 2)

That’s the case because according to the correct view, the Kuffār are addressed with the branches of the legislation. If they die upon kufr, from an angle the punishment will be based upon that for them not fulfilling the branches of the legislation and from them is the fasting. As for their present case of kufr, then they are only addressed with it after the actualization of the condition of Islām. It’s possible for you to return back to another Fatwā regarding this same affair under the title: “The Ruling of feeding the Kāfir During the Daytime in the Month of Ramadaan”. The knowledge is with Allāh and the last of our Duaa is: All praise is due to Allāh the lord of the creation. May the Salāh and Salām be upon our Prophet Muhammad, his family, companions and his brothers until the Day of Judgment.

Algeria 13th of Ramadān 1428/ September 25th 2007

Source: Taken from the website of Shaykh Ferkoos (may Allah preserve him):

http://ferkous.com/home/?q=fatwa-738

Translated by Abu Yusuf Khaleefah
2nd of Ramadān, 1436 H (06-19-2015)
Masjid Nur Allah, Queens, NYC