It depends who “he” is. If “he” is the father then it’s fine. When I first read it I thought that “he” was a son and he forgot that his father would judge him.

No, “He forgot the judge in the father.” does not sound natural or immediately clear to most native speakers. The intended meaning—“He forgot his duty as a judge in the name of fatherhood.”—is quite abstract, and the phrasing is unusual. Why does it sound unnatural? 1. Uncommon Structure – The phrase “the judge in the father” is not a standard English expression. Native speakers might struggle to understand what it means without additional context. 2. Ambiguity – It could be misinterpreted as “He forgot about a judge who was inside a father.” 3. Lack of Context – English tends to explicitly state relationships to avoid confusion, especially in abstract concepts like this. How to Make It More Natural? A more natural way to express this idea could be: ✔ “He forgot his role as a judge because he was thinking as a father.” ✔ “He let his fatherly instincts override his duty as a judge.” ✔ “He put fatherhood above his responsibilities as a judge.”

Maybe in a certain context it would make sense, but when I first hear it, it doesn't make sense.