The most important thing you as the healthy adult in the family need to do is respect and protect your kids as much as possible. You can’t change the fact that their other parent is a narcissist. That is something they will have to come to terms with. But you can do a lot to improve the situation for your children and help them develop coping skills.
Validate Their Feelings
A crucial thing to do for your kids is to validate their feelings. Since the narcissist parent routinely invalidates others through various means such as denial, shame, ridicule, and projection, your kids are especially in need of acknowledgement that their feelings are real, that they matter and are valid. Particularly for the child who is scapegoated (constantly targeted by the narcissist parent), it is vital to validate that their feelings of hurt and anger are justified and that they don’t deserve the treatment they are getting.