I played around with the PA Info Worksheet and overrode the Spouse Date of Death, changing it to 2018. This then updated the PA-40 form, so this answers my own question. Also, I downloaded a pdf of the PA-40 from the state site, which has 2018 as the year of death, not allowing you to enter a different year other than the tax year. Since there is no place to indicate why my spouse has not signed the form I will include this worksheet and type "Deceased on 4/5/19" in place of her signature.
