Is it permissible to give usurious money to one's brother with the intention of getting rid of it and helping him get married, knowing that he will not be asked to return it?

It is not permissible to deposit money in usurious banks when there is a choice, nor is it permissible to benefit from their interest. If money is deposited in them, then the interest must be taken and spent on general Muslim welfare, such as for those in need, and it should not be left to the bank.