There were quite a few slip ups in the series concerning Shawn Hunter and Topanga Lawrence's families...

For instance, in the first season Topanga has a sister named Nebula "Stop The War" Lawrence, who appears only in one episode and is never again mentioned. Topanga also mentions in season 1 that her mother's name is Chloe, but later on in the series it is Rhiannon.

Now for Shawn, who like Topanga, also had a sister in only season 1. Her name was Stacy, and was mentioned in one episode and never heard from again. In season 3 or 4 we find out Shawn has a half brother named Eddie, who also appears in only one episode and is then forgotten. So if he was Shawn's half brother, is he Jack's half brother also? Why do people put characters in the shows, only to have them disappear, and where do they all go?