Fyi - from wiki
Michael Rebus ("Mickey") is John's younger brother, who followed their father's career as a stage hypnotist. Although he and John look alike, their personalities are very different. Michael has a faithful wife (Chrissie), children, and a nice car. He is an important character in Knots and Crosses (1987), where he is picking up money dealing drugs and eventually goes to prison for it; he also hypnotizes John, allowing him to access traumatic memories of his SAS "training" to solve a case and also to resolve his undiagnosed PTSD. In The Black Book (1993) Michael turns up after doing his prison time and crashes at John's apartment, even though it has been rented to students. Although he seems carefree, doing drugs and sleeping with one of the students, he is reading up on therapeutic hypnosis and seems ready to make a career change; at the end of the book, he is going back to his family. Michael shows up at Samantha's bedside in The Hanging Garden (1998), and he is often mentioned in succeeding books as someone Rebus thinks he should get in touch with. The Naming of the Dead (2006) opens with his funeral, and Rebus's difficulty in mourning his brother is an underlying current in that novel.