Wow that family in unrealistically evil. Most evil parents (in more realistically written stories) would always believe, they are doing the benevolent/right thing for their child, even if that thing is psychological or physical abuse. Or they would at least see their child as some sort condamnable hooligan/danger for the rest of the family. Something that justifies their action. "Not to baby him any longer, even though parents helping their children to at least finish school is the standard". is not a good enough reason. They would come up with something they would believe themselves.
Something like,
"I'm at my wits end. Our eldest son always gets wind up in fights. He's not even trying to better himself. Even his younger sibling are effected. They had to talk him out of trouble. Doesn't he realize how dangerous that is? Doesn't he really care?"
"I believe he doesn't care at all. He even got fired. When he got himself a job, I hoped he'd change, but I guess lazy is lazy. We'll use this to educate him and throw him out. Maybe when he realizes how tough society is, he'll learn."
"Won't he lose the house?"
"I guess we'll have to buy his debts out and buy it ourselves (At a good price, that is.), before our family loses it. That money that good for nothing fool's deeds (Buying food and stuff. Deeds like living.) will cost us. We are way too good to him."
...you get the idea.
At least that bully + gang seems halfway "decent". Nothing over the top out of the world. Just greedy, horny bastards.