Being part of the Everett family came with its own set of advantages. They received a generous monthly stipend and fully-funded education, courtesy of the Everetts. They also enjoyed complete freedom over their lives and choices. Essentially, they had everything they desired.
Even when the Everett Patriarch became aware of the deceit within the branch families, he chose to turn a blind eye out of respect for his ancestors and refrained from punishing them. However, if he discovered that they were bold enough to scheme against his family despite all the benefits they received from the Everetts, he would undoubtedly sever all ties with them. By then, though, the damage would have already been done, and trouble would have been stirred.