"Every visit for the last seven years, she hasn't recognized any of us," Mulligan revealed of Nans, who now lives in a care facility in Wales. "When we leave, she won't remember that we've been there. But... there's a calmness and there's a companionship and these really fundamental feelings of being loved and being taken care of by people who, you know, family who really love you."
While Mulligan says her family has had "terrible visits where we've all ended up in tears," there are other times where "something really magical happens" with her 91-year-old grandmother, whom she says she has tried to reconnect with through music.
"She was a great lover of music and she taught me to sing and she taught me to play the piano and we realized that a lot of the times, just playing music and sitting with her was just the sort of loveliest time that we could spend with her," the Great Gatsby star said. "Music is something that often comes around for people who have dementia that it's a way of linking to the past, it's a nostalgic thing, it's a calming thing."
Earlier this year, Mulligan was appointed the Alzheimer's Society's first U.K. Global Dementia Friends Ambassador, and has supported the organization in raising awareness about the disease and how it affects families.
"It gets tiresome hearing dementia being the butt of a joke," she explained. "I think there's a general misunderstanding that in a lot of areas that dementia is a natural part of aging or it's just something that happens to you when you get older."
"I used to grow up hearing a lot of people referring to their grandparents having 'lost their marbles,' which is of course something that we'd never say about somebody who'd had cancer or heart disease," Mulligan added. "I think the understanding that dementia is a disease -- it's a disease of the brain, there are lots of different kinds of dementia, Alzheimer's is one of them -- and just spreading that awareness so that people really understand that this is a disease we have to fight."
While the Oscar-nominated actress supports her grandmother's struggle with dementia, she also has a lot to look forward to at home, with her 1-year-old daughter, Evelyn.