What should a son do when his father orders him to let his sister listen to music, claiming that her voice is 'awrah if she raises it during an argument when he tries to turn off the recorder?

Whoever witnesses an abomination, such as his sister listening to forbidden music, must denounce it through legitimate means: by hand if possible, otherwise by tongue, and failing that, by heart. He should inform his father about this with wisdom and respect. If he fears that his denunciation might lead to a greater evil, he should refrain from it and address the issue through indirect means. A woman's voice is not awrah (nakedness), but it is forbidden for her to speak in a seductive manner. In essence, the brother should discuss this with his father and sister amicably, explaining the impermissibility of the music, choosing the appropriate time and method.