What is the ruling on receiving salary from a Riba-based bank when it is the sole source of income, and what is the ruling on the deceased wife's salary remaining in this bank while only the Zakat is paid from it?

If the employer requires opening an account in a usurious bank, there is no sin, provided that the salary is withdrawn immediately upon its deposit, and not left in the account except out of necessity. The money deposited in the name of the deceased wife is an inheritance that must be divided among the heirs according to Islamic law, and it is not permissible to dispose of it individually or to withhold it from the heirs. Zakat is not obligatory on it unless the heir's share reaches the nisab (minimum threshold) and a hawl (full lunar year) passes over it. For any money given out as zakat without the heirs' approval, the husband is held liable for it.