How can one atone for the sin of spying on one's father, recording his private conversations, and playing them to one's mother, while feeling remorse for this act and disobedience, and fearing filial impiety?

Spying is forbidden; Allah has prohibited it in His Book and the Sunnah (definition) of His Prophet. Its prohibition is further emphasized when it concerns one's father, as it is considered a form of disobedience. Whoever has done this must repent and seek forgiveness from her father. If informing him of this matter would cause greater harm, then abundant seeking of forgiveness and supplication for him, striving to be dutiful to him, and working to reconcile him with her mother will suffice. Polygyny is permissible for whoever is able to be just between wives.