Is it permissible for her fiancé to enter into a partnership with his brother who refuses to give up usurious earnings and does not pay zakat, and is it permissible to invest money in a coffee shop?

It is not permissible to deposit money in usurious banks except out of extreme necessity, and usurious interest must be disposed of by spending it on charitable causes. The questioner must repent and pay zakat for the past years by calculating the balance each year and giving out two and a half percent (a quarter of a tenth), after deducting debts and usurious interest. If the money is unclear, he should strive to give out what clears his conscience. The nisab (minimum threshold for zakat) for banknotes is the equivalent of 85 grams of gold or 595 grams of silver. It is not permissible to partner with the questioner's brother if all his money is unlawful, and it is disliked to partner with him if his money is mixed. It is permissible to invest money in a cafe if the activity is restricted to selling permissible items.