All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallahu ‘alayhi wa sallam, is His slave and Messenger.
Everything that a Muslim does that benefits any human being or living creature deserves receiving a reward for it; the Prophet, sallallahu ‘alayhi wa sallam, said, "There is a reward in every creature with a moist liver (i.e. any living creature)."
Therefore, the food offered by the owner of this cafe is considered charity if he holds the intention of giving charity, regardless of whether it is served to Muslims or non-Muslims. It is allowable for the Muslim to offer the voluntary charity to Muslims and non-Muslims alike; however, it is better to offer it to Muslims, especially if they are fasting. If the fasting people break their fast with this food, its reward is greater, and he earns the same reward of those fasting people without their rewards diminished by that in the slightest. The Prophet, sallallahu ‘alayhi wa sallam, said, "Whoever provides the food for a fasting person to break his fast with, then for him is the same reward as the fasting person, without anything being diminished from the reward of the fasting person." [Ibn Maajah and others - Al-Albaani graded it Saheeh (sound)]
Allah knows best.