What is the ruling on eating food in the home of a friend who works in a tourist hotel, cheats customers, and deals with alcoholic beverages? And does that affect the acceptance of the prayer of one who eats this food?

Eating people's money by fraud and deception is forbidden, and it is consuming wealth unjustly, as Allah Almighty says: "And do not consume your properties among yourselves unjustly." It is forbidden to work in serving alcohol and pork, and its wages are unlawful gain. The friend who does this must be advised and warned of Allah's punishment. It is permissible to eat from his food if his money is mixed (unlawful and lawful), for the Prophet, peace and blessings be upon him, ate at a Jew's house, despite knowing that Jews deal in usury and take bribes. Your acceptance of his invitation should be with the intention of advising him and guiding him to the right path.