Pepi is a poor Spanish boy who temporarily became Homer's little brother/son.
History
When Bart joins the Bigger Brothers program and is assigned to Tom as his bigger brother/father, Homer, in revenge, signs up to get a little brother/son as well and gets Pepi. As Homer is his temporary bigger brother/father, he learns nonsensical things, such as the fact that whales are not mammals. Later, as Homer and Tom get into a fight, Homer is sent to the hospital (due to his spine getting cracked when he fell on top of a fire hydrant at the end), leaving Pepi without a bigger brother/father. Bart realizes that Pepi is more deserving of Tom than he is, so he pairs them up, and they walk into the sunset as the new father and son.
