I begin with the book Parallel, Parenting Solution.
Live a life of value and cling to that value as your touchstone. Let your truth shine so powerfully that it becomes a natural shield against every wave of negativity they throw at you.
Do the work, and allow yourself to feel anger only where it belongs. That keeps you from misdirecting that fire.
Books like Biff are fine. I won’t argue with a narcissist. Instead, document every observation so they can’t sway a judge or anyone else who wasn’t there about what really happened. There’s an art to finding a brief, informative, firm, and friendly approach. You learn it only through practice, and you can practice with someone outside the legal system.
Know this: nobody tied to the kids or the ex will ever be your friend. In the end, they’ll act to protect themselves, ad your narcissist will exploit that. Never lower your guard. At the same time, refuse to let the narcissist paint you as a stubborn antagonist. Show up, stand out, and keep your dignity.
And remember, you truly need a skilled therapist who understands living with a narcissist and the tangled complexity of navigating systems instead of just individuals.