Is it permissible for a wife to accept voluntary fasts and charity from her husband's money, the source of which is his bank salary, given that the wife does not have her own private money?

If the bank is Islamic, there is no harm in the wife consuming from her husband's money or giving it in charity with his permission. However, if it is a usurious bank, it is not permissible to consume from it except in cases of dire necessity, nor is it permissible to give from it in charity, because it is illicit gain. The husband must be advised to leave his job there and seek lawful sustenance.