Susan Daly is Ruby Daly's mother, and a minor character in The Darkest Minds.
The Darkest Minds
In The Darkest Minds, Susan Daly only appears once. In the beginning, it is Ruby's 10th birthday. That night, Ruby kisses both her parents goodnight, which, unknowingly to her, took all their memories of her. The next morning, Susan and her husband, Jacob Daly, don't recognize Ruby. They call the cops and lock Ruby in the garage. Before the cops can arrive, the PSFs come and take her away. Susan isn't seen again throughout the rest of the book.
Susan Daly doesn't appear in Never Fade.
In the Afterlight
In In the Afterlight, Susan, Jacob, and Grams visit Ruby in the hospital (after the camps are closed). They still remember caring for her, loving her. Ruby returns their memories, and her family is extremely protective of her from this point forward.
The Darkest Legacy
Susan Daly doesn't appear in The Darkest Legacy.