Hayden tells his friend how his brother mark had borrowed money from him years ago and didn't have the courtesy of returning it. they rarely keep in touch now. he also tells him that mark was the problem child of the family and would frequently steal from their father's wallet. hayden and john are an example of

The answer is Hostile Siblings.

Complete sentence:

Hayden and John are an example of hostile siblings.

Hostility (hostile) is being characterized by antagonism. It usually refers to a person or a person's action that is antagonistic and unfriendly.

In Hayden and John's case, they showed a hostile and menacing (a threat or danger) action.

The answer is an appellate court.