When the company pays separation pay (bonus, accumulated vacation, and so on) they are supposed to treat it like regular income, subject to FICA, medicare, and federal and state withholding, and report it on a W-2. (Revenue Ruling 2008-29)
Since your spouse passed in 2019, you can and should file a joint return this year. Be sure to check the box on your spouse's information page for "this person died during the tax year." And incidentally, you won't be able to e-file, since his SSN is probably blocked.
I would report the 1099 under your spouse's name as your spouse's income. Then, after entering the basic 1099 info, there is a page of special circumstances and one of those special circumstances is "this should have been on a W-2". Turbotax will prepare a substitute W-2 form and a special form to collect the 7.65% employee share of medicare and social security tax rather than the 15% self-employment tax. (The name and SSN mis-match will likely result in an IRS letter, that you should be able to answer by giving details of the situation.
(I might have a different answer if the payment was made in the year after your spouse's death, but since they both happened in 2019, I think the "should have been on a W-2" answer is the correct procedure.)
Or, you could ask the employer to rescind the 1099 and issue a proper W-2. Depending on how smart they are and who does their payroll.
If this money was included in his W-2 AND you received a 1099-MISC for the same money, then you need a smarter expert than me.
