Is it permissible to take a benevolent loan (qard hasan) from an Islamic bank to pay off part of a debt and deposit the remainder as saving certificates in the same bank without a fixed interest, and to benefit from the yield of these certificates to ease living expenses?

It is permissible for the husband to take out a benevolent loan for a permissible purpose if he is able to repay it. He is not obligated to take out a loan to pay off a debt he cannot afford. If he borrows or owns money, and he has a due and demanded debt, he must pay it immediately, and he is not allowed to delay it for investment. There is no harm in investing money in savings certificates at an Islamic bank and benefiting from their profits if it is a legitimate Mudarabah (partnership).