With this becoming public knowledge Albus would suffer another backlash and Lucius would be able to use this, in order to challenge Dumbledore on the Dumbledore seats in the Wizengamot, remove him from the ICW and fire him as headmaster, but he was saving this for the end. It would also help to announce the Order of Phoenix as a terrorist organisation and describe them that they were nothing better than Voldemort and his death eaters. With this he would have a different light side that would not listen to Dumbledore, but to him. Lucius needed to get rid of Dumbledore and Voldemort and the entire Wizengamot would be independent again without those two having any influence. He would have liked to have Aberforth Dumbledore as Lord Dumbledore since he was more reasonable and less senile than his brother and Aberforth didn’t like his brother one bit. The dislike came from the death of Arianna Dumbledore, Albus’ and Aberforth’s younger sister, who was a witch that had problems with controlling her magic and wasn’t able to control her powers. This had led to the death of Kendra Dumbledore, when their sister had a fit of accidental magic. But the breaking apart began, when Grindelwald killed Arianna in accident and Albus tried to cover it up and let his friend escape.