How can one clear themselves and their children of the doubt of the impermissibility of bank interest, given that there are currently fatwas permitting it?

A woman is permitted to accept maintenance from her husband if his wealth is mixed between lawful (halal) and unlawful (haram), provided she advises him to abandon the unlawful. However, if all his wealth is unlawful, she must demand lawful money from him; otherwise, she has the right to take the matter to a Shariah court. If the husband relies on a recognized fatwa that permits his work in a usurious bank and believes his wealth to be lawful, then his wealth is considered lawful, and he may spend from it on his family without any reservation for them in accepting it.