So sorry to hear about your book club member's ordeal. Sincere wishes for a strong recovery on all levels!
Don't know if I'd call it challenging, but I've been enjoying "Girls Like Us" by Sheila Weller. It's about Carole King, Joni Mitchell and Carly Simon, but is not a cut & dried bio of the three women. Where it would have been very easy to make this a 3-part bio, the author divides each section into a 4 or 5 year time span, and the narrative describes the lives of these women during that time, from their girlhood insecurities, family lives, and how their music shaped their lives (and obviously the lives of others). It's a glimpse back to the days when women weren't always so accepted in the music industry, to the wild and free times of the LA scene in the 1960's, to.... I'm not sure yet, because I'm still reading it. The author describes it in her acknowledgments as "three women, three moments, one journey." I'm enjoying it very much and my boyfriend is anxious to read it when I'm done. In the back of the book, the author poses questions and topics for discussion, too.