I choose to believe that Scrooge's sister is adopted, and therefore, they are not related by blood. I had their entire future planned out, and I'm too far gone with the Debbigail ship to turn back now, they're my Ducktales OTP.
@BeatricebaudelaireII Scrooges sister is not adopted, its what the show writers say is true, its THEIR universe. You have gone a bit far with the theory