Danny's Dead and Who's Got the Will? - S4-E12
Continuity mistake: At the start, when Fran joins Niles, she's holding a green mug in her left hand and a muffin in her right hand. But the mug and muffin suddenly switch hands when Fran and Niles head to the sofa.
Answer: Mr. Sheffield needed someone to manage the kids, not necessarily babysit them. Brighton was a Bart Simpson type, Maggie was shy and awkward and Gracie had personality issues.