Lady Yvette Bristow (nee Landry) is the adoptive mother of Lula Landry, John Bristow and Charlie Bristow. She and her husband, Sir Alec Bristow, who died a while before the events that take place in The Cuckoo’s Calling, adopted Lula shortly after Charlie died. Yvette had always wanted a girl, so she adores Lula and, by some reports, spoils her. Many people view Yvette as being overly emotional toward Lula and a difficult mother.
Yvette’s brother is Tony Landry. Their father was a senior partner in the law firm Landry, May, Patterson before Tony inherited the share in the business.
During The Cuckoo’s Calling, Yvette is seriously ill from cancer. She’d previously had surgery, but after Lula died the cancer returned. Her son, John, and her brother, Tony, both look after her during her illness, along with private nurses.
Cormoran Strike visits and interviews Yvette toward the end of the book, in the final stage of the investigation.