Is the money remaining after selling the car and paying half of the usurious loan to the bank permissible (halal), is the questioner sinful for taking the loan in her name, and is her husband justified in blaming her for that?

The husband erred, and the wife sinned by taking the usurious loan, unless there was a necessity, and both must repent. The wife's insistence on selling the car is permissible if it is to alleviate financial distress or to get rid of usurious interest, and the entire price must be spent on repaying the loan unless there is a necessity. However, if the wife's insistence on selling is not for one of these reasons, she should not do so, and she must obey her husband. There is no objection to the amount retained from the car's price; it is the husband's property, unless retaining it prevents the repayment of the debt and getting rid of usury.