What is the ruling on the increase resulting from the annual interest in the savings account opened in my name with money from my deceased father, and is it permissible to use it to pay off usurious debts on behalf of my brother or to pay arrears on my father’s properties in order to receive them, and what is the ruling on inheritance from other bank accounts in usurious banks whose origins have not been verified?

Opening a savings account takes the ruling of the bank: it is permissible if the bank adheres to the provisions of Islamic Sharia, and impermissible if it does not. The bank mentioned in the question is an interest-based bank, therefore, it is not permissible to open an account with it. The decision of the Islamic Research Academy in Cairo in 1965 clarifies that interest on loans is prohibited usury, and both much and little usury are forbidden. Lending and borrowing with usury are forbidden except in cases of necessity. Bank operations such as current accounts and cashing checks are permissible, while time deposits, opening lines of credit with interest, and all types of lending in exchange for interest are usurious and forbidden transactions.

As for the questioner, he owns the halal principal of the inheritance and should dispose of the usurious interest by spending it on public welfare or for those in need. If he does not know the exact amount, he should estimate and dispose of it. It is permissible to give the usurious interest to pay off his brother's debts if he is needy, but it is not permissible to spend it for the questioner's own benefit; rather, it must be spent on charitable causes.