Why are there no books for mothers of narcissistic daughters?

This premise is incorrect. There are many books available for mothers of narcissistic daughters, such as:

* "Will I Ever Be Good Enough? Healing the Daughters of Narcissistic Mothers" by Karyl McBride

* "Mothers Who Can't Love: A Healing Guide for Daughters" by Susan Forward

* "Daughters of Narcissistic Mothers: Reclaiming Your Life and Finding Your True Self" by Stephanie Donaldson-Pressman and Lisa F. Firestone

* "Toxic Parents: Overcoming Their Hurtful Legacy and Reclaiming Your Life" by Susan Forward and Craig Buck

* "The Narcissistic Family: Diagnosis and Treatment" by Robert A. Rhoades and Jonathan W. Stewart