Who is Doro and Leo from The Memory Keeper's Daughter and what is their importance?

Doro lives with Leo in an old house in Pittsburgh that was her childhood home. The house once had a field of daffodils next to it, but now has a freeway instead and is in the middle of town. Doro is an educated physicist and an academic, like her father once was. Her father, Leo, is suffering from dementia, which is why Doro hires Caroline Gill as an assistant for him. Leo challenges Caroline and congratulates her on being the only person who is able to handle him.