Can a ruler adjudicate a case involving their parents or children?

Primary text

There are two scholarly opinions regarding whether a ruler may judge a case involving their parents or their children, or someone whose testimony would not be accepted on their behalf. The first opinion states that the ruler cannot personally judge such a matter, and if they do, the judgment is not executed. This is the position of Abu Hanifah and Ash-Shafi'i because their testimony is not accepted in their favor, thus their judgment is not executed for them, similar to their own self-interest.