The quarters crashed across Rachel’s place setting so loudly that every conversation at Mom’s 79th birthday dinner stopped. My 10-year-old son, Noah, stood beside the table clutching the empty jar where he had saved nearly $40 for a new bicycle. “This is for Aunt Rachel,” he announced. Six months into chemotherapy, I had depended on my sister to help Mom, who lived nearby and struggled with arthritis. Rachel had moved into our house after her boyfriend disappeared with their savings, and she promised to manage everything while I recovered. None of us knew her help came with a price.