The man mentioned in the question

A: The woman is only required to repay the principal loan, which is 300 dinars if the reality is as you have mentioned. The extra money is Riba, which the wife is not obliged to pay and the creditor is not obliged to require or take. This is if her husband left money from which she can repay the loan, but if he left nothing, there is no obligation on her. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.