It wasn't until breaking up with my covert narc ex that I decided to explore more about my childhood.

I was the child of a narcissist mother. Being raised by a narcissist led my brother to become a narcissist and me to become codependent. Narcissism and codependency are the result of childhood trauma/neglect. This causes Complex PTSD.

What he is doing will essential teach his daughter to repress her emotions. It is wired unconsciously into her before she even has a conscious memory. He is programming her with negative core beliefs: "It is your fault" (sense of guilt). "When you are in pain, no one will comfort you." etc.

Are you still with this person? How can you stand by and witness this? If the situation is abusive then you need to leave. Emotional abuse is still abuse.