Christopher Brown is also a city mayor, a position of high power. Although not as high as Lucy Campbell's, he's not someone John Brown can order around. However, with the anti-corruption wave in SSUP Country growing stronger, as a mayor, he's very sensitive to such matters. If Samuel Johnson keeps indulging his daughter and this gets out online, it won't just be Samuel Johnson who is in trouble; the entire city will feel the immense pressure.
John Brown sent the video directly to him, giving him the chance to handle it discreetly, without causing a national frenzy that's hard to contain. Thus, he immediately made his decision.
Despite Samuel Johnson's usual arrogance, a call from the mayor means his political career is completely ruined, and once he enters the Integrity Department, he'll likely never see the outside of a cell again. He immediately became dispirited, far from his former arrogance.
"Dad! Dad! What happened?" Rachel Wilson asked loudly, still ignorant of the crisis.