Or HaChaim on Genesis 34:27/אור החיים על בראשית ל״ד:כ״ז

1 בני יעקב באו על החללים, The sons of Jacob came upon the slain and plundered the city. This means that all of Jacob's sons participated in the looting. They were entitled to do so as they had all suffered humiliation by the rape of their sister. Each one was entitled to take his share. Maimonides has written in Hilchot Na-arah Betulah chapter 2 that the court gives due consideration to the respective stature in society of both the rapist and the victim before it decides the amount of money to award to the victim's father and to her family. Dinah's brothers were all included in what Maimonides described as the victim's "family." This is why they all assembled there to determine their respective shares of the compensation due them. When they determined that the combined wealth of the townspeople was not adequate, they simply carted off all their belongings on behalf of their father to whom all this belonged. Although we have a rule that if someone is executed for a crime we do not exact financial penalties in addition, this rule does not apply to Gentiles (compare Tossaphot Eyruvin 62).