Is one who listens to shaylat and music in the car sinful if he was unaware of the music's presence in it, and if the brother gets angry when we ask him to change it, should we cover our ears, and should one cover their ears if they hear a small amount of music during prayer?

It is not permissible to listen to music or chanting that includes something forbidden. You should advise your brother and remind him to fear Allah. If he does not respond, it is permissible for you to put something in your ears so that you do not hear the forbidden, following the example of Ibn Umar (may Allah be pleased with them both) when he heard the sound of a shepherd's flute. It is not necessary to block your ears from hearing during prayer or outside of it. There is no sin upon you for merely hearing something if you did not intend to hear it and you disliked it in your hearts, for there is a difference between hearing (sima‘) and actively listening (istima‘).