What is the ruling on disposing of inherited money that is under guardianship in a usurious bank, with accumulated interest, and is zakat obligatory on it retroactively, and how is it to be paid?

It is not permissible to deposit money in an interest-based bank except out of necessity. Interest-based earnings must be disposed of by spending them on Muslim welfare. Zakat (definition) on wealth for past years must be paid if the wealth reached the nisab (definition). It was obligatory for the sister to promptly withdraw the money from the bank, dispose of the interest, and pay Zakat. She must now repent and promptly rid herself of the consequences of these sins.