In "The Case of Impossible Education" (Brenner v. The Little Red School House), how does the court define "impossibility of performance"? Would that be answered by how the jurisdictional court describes in the information of the case I found at https://law.justia.com/cases/north-carolina/supreme-court/1981/46-4.html

And according to the court's ruling, what effect does a frustrating event have if it was foreseeable? I do not understand this question.