When Papa moves into the barracks, things get really crowded, but not because of his actual body—nope, it's because he's a bitter and depressing brooder who never leaves the barracks and gets his wife to bring rice and canned fruit so that he can make his own brand of alcohol.
In other words, he's a drunk too. Good times.
At first Jeanne thinks Papa's struggling partly because of how the army treats him and because he thinks he ought to be above all of this, but then she finds out that people at camp think her father is an inu, which means "dog" but also means that he's an informer, someone who ratted on other Issei men to get his freedom from Fort Lincoln early.
People think that because he worked as an interpreter, he must've used information about his Issei brothers and sold them out.
Papa can't deal with all these rumors so he drinks.
When Jeanne and her mother confront Papa about the rumors, Papa explodes and goes on a rampage.
He threatens to kill his wife, and she—after a point—basically tells him to do it.
But Kiyo jumps up and punches his father in the face.
Then he runs away to one of his sisters' barracks where he hides for two weeks.
Finally Kiyo returns and apologizes because he wants order to be preserved.
Papa accepts him, but things have definitely changed. The "center has collapsed" (22)… and there's nowhere to run.