Is one who works in a fast-food restaurant sinful if he does not listen to music, but works in a place where music is played by the restaurant owner's father, and he delivers meals to homes and shops that may be salons or music stores?

Listening to music and musical instruments is forbidden. If a person is in a job where they are forced to listen to music and cannot turn it off or leave the place, they are permitted to stay in that job if they are in need of it. It is also permissible to deliver food to establishments where there are forbidden things, such as music.