So he sold a rental and then you sold his home that was in the estate? There's nothing you can do about how he reported the sale on his 2019 return because he DID elect out of installment treatment.....he COULD have reported the sale on an installment basis but he chose not to....that's that. The estate will have no gain if his home was sold for its FMV on the date of his death BUT you will have to report the sale so the IRS knows there is no gain......otherwise all they see is gross proceeds from the sale.
