What is the ruling on visiting the home of someone who works in a usurious bank, and eating and drinking their food and beverages? Does the same ruling apply to their children?

Consuming usury and working in institutions that deal with it are major sins. Whoever does not consume usury is still affected by its dust, and every body nourished by unlawful earnings is best suited for the Fire. The questioner did well in objecting to consuming money earned unlawfully by her husband's brother; this is the safest and most pious stance. Scholars have differed regarding consuming unlawfully obtained money: if all the money is unlawful, then it is forbidden to eat from it. If most of it is unlawful, it is disliked. If what is eaten comes directly from unlawful sources, it is forbidden. If the unlawful portion is minor, there is no harm. The brother must be advised, the unlawfulness of his work explained to him, and he should be helped to rid himself of it. Children are a trust that must be preserved by ensuring their food, drink, and clothing are pure, so they may become accustomed to virtues. Regarding the sister-in-law's work as a teacher: if she teaches women or boys, there is no harm in eating her food. However, if she teaches adult men, it is an unlawful act, and the money earned from it takes the ruling of unlawful money.