Is the husband considered responsible for his former wife's debts, and is the wife held accountable for these debts if she acquires wealth, and what is the fate of the spouses if they die before settling them?

The debt incurred by the wife is her sole responsibility, and the husband has no connection to it and is not accountable for it. She must repay her debt from her earnings or other means. If she dies without repaying it, the debt remains tied to her responsibility, and Allah will exact justice for the creditors from her, unless they forgive her, or unless Allah repays it on her behalf due to her sincere intention, as stated in the Hadith (definition): "Whoever takes people's money with the intention of repaying it, Allah will repay it on his behalf; and whoever takes it with the intention of destroying it, Allah will destroy him."