Mrs. Mulligan was the care-taker for Sarah Frobisher-Smythe in Season 1 before Sarah died. She brings Sarah to the House to visit it again. While Sarah is talking to Victor, Trudy takes Mrs. Mulligan on a tour of the house. She gave the box of Sarah's possessions to Nina.
Mrs. Mulligan was the caretaker for Sarah. They were always very nice to each other. She was always there for Sarah and always helped her to the best of her ability. She thought that Sarah's name was Emily.
She (and everyone else) thinks Sarah's name is Emily Grant and she thought Sarah was deaf because she once shouted in her ear.