1x7 - Maniac Mansion

Fred is playing around in the living room when Lenny Orca, Harry's long-lost boxing twin brother from Canada, comes to the door. Lenny tells the family that the reason he's taken so long to visit is that he's come home to die. He's OK with it, and the kids are too, but Fred, Casey and Idella are very concerned about it and decide not to tell him about Harry because it might kill him. He finds out anyway, but the doctor phones and tells him that he's not going to die. He promises to visit again at Christmas, gives the kids loonies, and makes up with Harry for an incident at the orphanage.