It depends on if you received a 1099-S or not.
Since you did not have an appraisal at the date of death, then you could probably make the assumption that since it was sold within 1 year after his death, that it was sold at fmv.
Since it was your father's principal residence before death and it was not used in a difference manner after his death, then it will still need to be sold as a personal asset and a personal loss is not deductible. You can mark the box that a personal loss is not allowed in the software per Pub 559.
If the 3 children inherited the house at death and then sold it and you each received a separate 1099-S for your 1/3 of the selling price then you would enter the 1099-S into your return using "inherit" as the acquisition date and long-term as the holding period of the asset. You would show the selling price as the selling price and if you paid closing costs, you would include them in the adjusted basis amount.