What is the ruling on dealing with foreign banks and keeping money in them, and is it permissible to take the interest resulting from deposits in banks and then give it to needy relatives, or must it be spent in other areas?

Unlawfully acquired money whose owner is unknown does not become the property of the person who has possession of it. It must be disposed of by spending it on public welfare, such as for the poor and needy, or other charitable causes. There is no harm in the poor recipients being relatives or neighbors. It is not permissible to deposit money in interest-based banks, as this assists their owners in sin, unless one fears their money will be stolen or usurped. In such a case, it may be deposited in an account that does not yield usurious interest, out of necessity.