There are already some great suggestions in this thread, but I’d like to recommend some second-generation Holocaust texts. (Second-generation, here, refers to texts written by or about the children of those who witnessed the Shoah):

The Holocaust Kid by Sonia Pilcer (story cycle)

I Was a Child of Holocaust Survivors by Bernice Eisenstein (graphic novel)

The Waiting Room by Liza Kosher (novel)

The Speed of Light by Elizabeth Rosner (novel)

Secondhand Smoke by Thane Rosenbaum (novel)

Many of these could be better classified as autobiographical fiction (that is, they blend lived experiences with fictive elements).

For context, I’m a literature PhD student who has taken classes on Holocaust literature and taught several survivor and second-generation short stories and novels. In my experience, most folks find it’s easier to comprehend and discuss second-generation texts than those written by survivors, especially in more casual settings (such as a book club). Maybe this is because second-generation texts allow groups to discuss not only the history, but also the memories, traumas, and legacies that that history continues to leave in its wake. You could also have conversations about family dynamics, especially parent-child relationships, domestic space, communication styles, etc.

I hope your choices go over well!

(Edited for formatting—damn you, mobile!)