折疑論 2.184

2.184

且父母有非行。而子能爭之。使不陷於不義。猶得為孝（孝經云。父母有爭子。則身不陷於不義。正謂此也。而猶得稱為孝焉）。

Furthermore, if parents commit misconduct and their child is able to remonstrate with them, preventing them from falling into unrighteousness, this can still be considered filial piety (The Classic of Filial Piety says: 'If parents have a remonstrating child, their persons will not fall into unrighteousness.' It refers precisely to this, and it can still be called filial piety).