The narrator in "The Interlopers" doesn't actually mention any famous lawsuits. The story focuses on the feud between Ulrich von Gradwitz and Georg Znaeym, who are caught in a storm and trapped under a fallen tree. The entire story revolves around their past feud, their present conflict, and the possibility of reconciliation.
The narrator is an observer, relating the events as they unfold. There's no mention of any specific lawsuit or legal battle in the story.
Are you thinking of a different story? Perhaps you're mixing up "The Interlopers" with another tale?