Not really getting what the teacher gets out of making the child bully the primary owner; even though hes rich, there is no talk about payment or funding of his brainwashing research. Plus, since the master only needs saliva to initiate control, why not enslave the rich boy for any benefits he'd get, etc.
And once the mother willingly joined the other side believing the son was the bad guy, there wasn't any hope of him normally freeing her, so actually make use of the video they sent you of brainwashing her to at least attempt (and fail since rich boy will own the police) to do ANYTHING.