Oh, and one more final note. When you go the e-file the return if you get a rejection messge of "SSN LOCKED" that indicates that whoever handled the final arrangements for your spouse, did their job. They would have notified the social security administration of their passing. In turn, the IRS pulls all taxpayer information from the SSA systems. So that's how the IRS will know your spouse has passed.
In such a case, the IRS will *LOCK* the SSN so that it can't be used fraudulently. so if you e-file and it's rejected as above, you will have no choice but to print, sign and mail the return to the IRS with the appropriate documentation that shows why only you and not your spouse signed the return. If it gets to that, we can help you with the appropriate documentation.
