First of all, I pray that his condition will not be terminal.
But, if it is, may God grant you peace and him eternal salvation.
Now, let's address your question.
If you had been married 35 years, you'd still not be responsible for his personal debt.
Unscrupulous lenders and debt collectors will sometimes prey upon you in your bereavement.
Ignore them, as no surviving relative or spouse is ever responsible for the debts of their deceased loved one!
Again, I pray for you and your spouse as you go through ths dark and difficult trial.