The title is:
Finding Grace / Alyssa Brugman.
RACHEL HAS JUST graduated from high school and thinks she knows everything. Well, maybe not quite everything. Then she meets the mysterious Mr. Preston, who offers her a live-in job looking after Grace—a brain injured woman with a lovely house, grasping sisters, feral neighbors, and a box full of unfinished business. As Rachel tries to cope with the demands of her employment and the start of college, she’s also determined to fit together the pieces that were Grace’s former life. The more she finds out about the woman in her care, the more Rachel finds herself. Children’s Book Council of Australia Awards’ Shortlist for YA