Can a ruler judge a case where one parent is in dispute with the other parent or with their child?

Primary text

According to the first scholarly opinion regarding judging cases involving relatives, if a dispute arises between the ruler's parents, or between their children, or between a parent and a child, the ruler cannot judge between them. This is based on the view that the ruler's testimony would not be accepted for one against the other in that specific conflict, thus preventing judgment, similar to a dispute involving a complete stranger.