Is there a way to assign a father to an already created Sim in Sims 4?

So I made a sim family with a daughter (my main character) along with her mom and brother but no father as I wanted her backstory to be that the husband was a firefighter who died in a fire so I made the family first without him, and then moved the mom and brother out so I could focus on the daughter solely. Then I realized I could’ve still made him but just as a ghost so I did, but now he’s not registering as the son’s dad and the brother is now showing up as my girl’s half sister. Is there a way to make him the dad of the son or no?