Santa's Little Helper's brother

Santa's Little Helper's brother is the brother of Santa's Little Helper who lives with country folk.

History
When Marge discovered that Homer let the Springfield Mafia make a pornographic film in the Simpson house in return for letting him off on the money he owes them, she stormed out and drove to the coastline, where she rang Homer and was terrorized by a manatee who was banging on the phone box. A doctor named Caleb Thorn took the manatee away and introduced himself to Marge. They began to help manatees together, and when Homer arrived at the beach, having been told Marge's whereabouts over the phone, Marge refused to go home with him because he'll be sorry for a few days and then go back to his sleazy self. Homer, who'd brought the kids with him, and after driving through many un-heard-of fast food restaurants, decided to visit their country cousins. During dinner, Homer told them that Marge had been killed, and afterwards Bart asked one of the kids he was playing with how they were related, and he recalls that their dogs were brothers.

The Simpsons' "country cousins" will have presumably bred two greyhounds to produce Santa's Little Helper and his unnamed brother, as people living in the countryside often do, however country folk do not usually breed greyhounds, so it's possible they bought them off someone else. Les, Santa's Little Helper's previous owner, will have presumably bought Santa's Little Helper to either replace another of his racing dogs or to just begin a reputation for dog racing. Sometime after the Simpsons adopted Santa's Little Helper after he was thrown out by Les, the family found the family he, presumably, originated from or had a sibling owned by them.