@StarLily501 I am not sure if my explanation will make sense as to why his was disowned and Aimme's parents were also punished but I hope it helps! 

He just got fired by the crown Prince as a royal knight, a vice commander to the princess residence to be exact. Although in modern time this may be nothing then just losing a job but to a noble the dishonor he brought not only to his family, but the royal family and Lyddy's family, is equal to a social death sentence, and your social standing is a big part of nobility. His actions will effect how people interact(make deals with merchants) with his family and that is a big part of how mobility made money. Of course you also have nobles who will now look down on them which is something no noble wants.
As for Aimme's parents, to put it in modern terms -they work for the government and their child stole money from the government so they lost their jobs(keep in mind they were already struggling with money) btw in stories with nobility a lot of times the whole family is helped responsible for the actions of other family members

@DoctorEvil61 What makes me mad is that she says she is doing all this to "protect" the other 3 girls but as the guild master she just joint a coup which we all know it WILL fail she pretty much sentence those girl to death because anyone who is associated with the coup is a traitor to the crown.

Oh and let me add one more thing, she has never read any novels she IS a character within the novels and her role was always the villains daughter that die in the end. She herself only knows that villains die while protagonist gets to live a good life.