@lucky1234 wrote:
My father's business was not a LLC or partnership. It was a sole proprietorship. Would the linked version still be applicable?
During this year, his wife was still alive. Can we file my dad's taxes for this year as married, but filing separately?
Most of the time, spouses file "married filing jointly" and your father's wife would have been allowed to file a joint return the year he died. If she did, then a return was already filed for your father. If it was incorrect, then the wife needs to file an amended return. You can't change a return from "married filing jointly" to "married filing separately" after the original deadline (which was April 15, 2018), and you can't file an amended return for just your father, it has to be an amended joint return signed by the wife.
If the wife filed as married filing separately, or single, or filed jointly with a new spouse, then no 2017 return was filed for your father and you can do that now. You would file a form 1040 with schedule C for the sole prop for income and activities up to the day he died, and might have to also file a 1041 estate return for income and activities that occurred after the date of his death. I agree with the recommendation for professional assistance.
