Malignant narcissists ( the type that do the most damage) learn at an early age to mimic normal behavior in order to get what they want but behind the mask, they are wholey self serving predators who see others as sources of “supply” rather than individuals, persons, with separate inherent value. This world view wrecks havoc on the family unit. There is no such thing as a healthy family dynamic when a narcissist is involved but of all narcissists the covert malignant narcissist ( or socialized sociopath if you prefer the term) is the most dangerous. They operate so far below the radar it often takes years for those close to them to recognize the source of the familial dysfunction and anyone who does notice will be ruthlessly attacked, discredited and ostracized. Trying to build a healthy family unit with a covert malignant narcissist is virtually impossible. The most common outcome is a heavily divided dysfunctional family unit defined by the narcissists hiearchiel power games in which the narcissist is at the top and everyone else is below and any dissenters are discredited and banished.
The narcissist actually believes this is an ideal outcome because control and power (winning) is in the mind of the narcissist all that matters. The narcissist suffers a dysregulated ego and cannot allow themselves to ever feel “less than” anyone even their own spouse or children.