Let's say you split the family into two camps. Your camp and the other camp.
You have lots of interesting work now, building consensus against "Them" to keep your camp loyal to you. You collect and jealously guard Allies. It's so satisfying when you can lure a wavering family member over into your camp.
You have successfully redefined the concept of family. Family, which was once a refuge from the power struggles of the world, is now a grinding power struggle of it's own.