Do not report this 1099-C on your return. It was your deceased husband's debt, not yours, and there is no requirement for your to report it on your return.
Your husband''s final return was filed in 2019 (joint, with you. There is no way to report this 1099-C on a 2020 tax return.
Since there is no open estate, there are no estate assets and no estate return requirements. You can either file the 1099-C with your 2020 tax files or discard it.
