Here’s a useful feature for writing family drama and complex relationships:
The Unspoken Contract

In the landscape of human experience, few things are as messy, beautiful, or inherently dramatic as the family unit. We often hear the phrase "family comes first," but for many, that priority is a double-edged sword. Whether on the silver screen or around the Sunday dinner table, family drama storylines resonate so deeply because they mirror the most fundamental struggle of our lives: the effort to be seen, loved, and understood by the people who know us best—and sometimes hurt us most. The Anatomy of Complex Family Relationships

To make relationships feel "complex" rather than just "angry," you need Ambisexual Conflict

Triangulation: This occurs when two family members use a third person to communicate or take sides, creating unstable alliances rather than direct, healthy resolution.