Who is Carol from Anywhere but Here and what is their importance?

Ann's aunt, Carol, has had a very interesting life. She volunteered during World War II, and she served in Chicago, before being sent to France. While in France, she met and married a handsome, young member of the French Resistance, who later died a tragic death. Carol never mention this to her family back home, and she goes onto to live a quiet life in Bay City. When Adele goes home..... she goes to Carol's.