The Return of Maggie Beckett - S5-E9
Other mistake: The group slides to Fresno, where there is a monument to Maggie Beckett and the astronauts that were lost on an Intrepid mission to Mars. On the memorial stone, her name is misspelled as Maggie Becket, not Beckett as everywhere else.
Chosen answer: Quinn's brother was going to be a recurring character, so "introduced" in this case referred to the actor becoming a semi-regular.
Jean G