Extended family does not seem to matter. The brother of one of the top leaders of the party (Yu Zhengsheng) has defected to the US long before Yu being elected into PBSC (Politburo Standing Committee), the board of directors for China inc.
Chinese society is extremely family-oriented. Xi Jinping has been much more aggressive with government power than his immediate predecessors, but his biggest themes are conservative and traditional. Lots of taoism and confucius.
I'd posit that their government doesn't go after (han chinese) families because it turns one dissident into 50.