Is the husband excused for taking a usurious loan to pay off his brother's debt after his debts escalated due to buying an apartment, or is his action considered an act of disobedience despite his knowledge of its prohibition and his feeling of pain?

Allah has forbidden usury and threatened those who practice it with war from Him. The Messenger of Allah, peace and blessings be upon him, cursed the one who consumes usury, the one who feeds it, its scribe, and its two witnesses. It is not permissible to engage in usury except out of a necessity recognized by Islamic law, such as fear of perishing or extreme hardship. However, housing is a necessity that can be met through renting, so it is not permissible to resort to a usurious loan to purchase it if renting is available. Paying off debt is obligatory, but it is not permissible to take a usurious loan for it. The solvent debtor has no need for a usurious loan, and the insolvent one must be given respite. Therefore, it is forbidden for your husband to take a usurious loan to pay off his brother's debt. The brother must give him respite, and your husband must repent from engaging in usurious borrowing. If he can repay the principal of the loan without its interest, then he should do so. Otherwise, he should repay it with its interest, as he is in the position of one who is compelled.