Because literally the sentence would translate to something like "Is basketball pleasing to your brother?" Basketball is actually the subject of the sentence.
Although that is a literal translation, I don't think anybody would generally say that in English.
Are you thinking the (basket)ball? I think that's el balón de baloncesto or la pelota de básquetbol for the ball and el baloncesto/el básquetbol for the sport. Or anyway, it used to be!