Please accept my condolences on the passing of your husband! I don't know if you want to or if you think you have to file married filing separately. The IRS allows the spouse of a deceased spouse to file as married filing jointly for the year of death. So, if you want, you may file as MFJ for 2016. I have included a Link below that will highlight the benefits for filing married filing jointly instead of married filing separately:
https://ttlc.intuit.com/questions/1894449-is-it-better-for-a-married-couple-to-file-jointly-or-separ...
