Is it permissible for the owner of a restaurant to sell food to those who are not fasting and to kuffaar during the day in Ramadaan?
Question

I am living in a foreign land and I have a small restaurant. I see some Muslims who are not fasting – and there are many of them – who want to eat in my restaurant during the noon hour. What is the ruling on selling food to these people who are not fasting, and selling food to non-Muslims?.
Praise be to Allah.Firstly: 
In many answers on this site we have mentioned the warning against settling in kaafir countries, because of the danger that that poses to a man’s religious commitment and that of his family too. The man cannot give his family the Islamic upbringing that he wants. Work is no excuse for a Muslim to live in those countries. See the answer to question no. 13363. 
Secondly: 
With regard to your question, you should note that it is not permissible for you to offer food to anyone to eat during the day in Ramadaan, unless he has an excuse that allows him not to fast, such as one who is sick or is travelling. There is no differentiation between Muslims and kaafirs in this matter. The Muslim who is not fasting is commanded to fast, so he is sinning by not fasting. Enabling him to eat and drink during the day in Ramadaan is helping him in sin and transgression. The command to fast and all other rulings are also addressed to the kaafir, but before that he is required to utter the Shahaadatayn (the twin declaration of faith) and enter Islam. On the Day of Resurrection the kaafir will be punished for his kufr and for the laws of Islam that he did not follow, so his punishment in Hell will be increased. 
Al-Nawawi (may Allaah have mercy on him) said: 
The correct view which is followed by the majority is that the minor issues of sharee’ah are addressed to the kuffaar, and silk is haraam for them as it is haraam for Muslim men. End quote. 
Sharh Muslim, 14/39. 
Shaykh Muhammad al-Saalih al-‘Uthaymeen (may Allaah have mercy on him) was asked: 
How will the kaafir be brought to account on the Day of Resurrection when he is not required to follow the obligations of Islam? 
He replied: 
This question is based on a misconception. The same is required of the kaafir as is required of the believer, but he is not to be compelled to follow it in this world. The fact that it is required of him is indicated by the passage in which Allaah says (interpretation of the meaning): 
“Except those on the Right (i.e. the pious true believers of Islamic Monotheism).
40. In Gardens (Paradise) they will ask one another,
41. About Al‑Mujrimoon (polytheists, criminals, disbelievers) (and they will say to them):
42. ‘What has caused you to enter Hell?’
43. They will say: ‘We were not of those who used to offer the Salaah (prayers),
44. ‘Nor we used to feed Al‑Miskeen (the poor);
45. ‘And we used to talk falsehood (all that which Allaah hated) with vain talkers.
46. ‘And we used to belie the Day of Recompense”
[al-Muddaththir 74:39-46]
If they were not being punished for not praying and not feeding the poor, they would not have mentioned that, because there would be no point in mentioning it in this situation. This indicates that they are being punished for not doing the minor issues enjoined by Islam. As this is implied by the texts, it is also implied by reasoning. If Allaah will punish His believing slave for what he failed to do of religious duties, how can He not punish the kaafir? Moreover, the kaafir will be punished for all the blessings that Allaah bestowed upon him of food and drink etc. Allaah says (interpretation of the meaning): 
“Those who believe and do righteous good deeds, there is no sin on them for what they ate (in the past), if they fear Allaah (by keeping away from His forbidden things), and believe and do righteous good deeds, and again fear Allaah and believe, and once again fear Allaah and do good deeds with Ihsaan (perfection). And Allaah loves the good‑doers”
[al-Maa’idah 5:93]
The apparent meaning of the verse is that there is no sin on the believers for what they have eaten. What this implies is that there is sin on the kuffaar for what they have eaten. End quote. 
Majmoo’ Fataawa al-Shaykh Ibn ‘Uthaymeen (2/question no. 164). 
Based on this, it is not permissible for a Muslim to offer food to a non-Muslim during the day in Ramadaan, because the minor issues of sharee’ah are addressed to the kuffaar too. 
In Nihaayat al-Muhtaaj (5/274) it says that the scholars regarded it as haraam to sell food to the kuffaar during the day in Ramadaan. See also the answer to question no. 49694. 
And Allaah knows best.