Two people in a family rarely want opposite things. They usually want the same thing (safety, respect, love, to be heard) but have different, clashing methods of getting it.
Provide a list of to study for masterclass examples of these dynamics. Let me know which area you'd like to focus on first! Writing Family in Fiction - Writers & Artists
Claire stood between them, her voice trembling but clear. "And I was the one who answered the phone every time one of you wanted to complain about the other. I was the bridge, and I’m tired of being walked on."