This is so ironic that this same Judge Emmet was the good judge in Sidney Powell's fight against prosecutorial corruption. In her book License to Lie she describes him as a good judge.

But in Flynn's case, he has already turned into a monster. This shows that almost every person will get turn to the dark when the oppurtunity presents itself, and very few people stay intact. If there was even one skeleton in your closet, you have no choice but to turn to the dark (since even if you decide to commit suicide, the DS will hurt your family. So there is no escaping)

Emmet's skeleton in the closet was his son. There was an incident between his son and his gf (who was another Judge's daughter) and either she was badly hurt or killed by the son, and he had to sell out a lot to save him that time. I am pretty sure this is the leverage they used on him.