Problem with my dads ipod?

So my dad is trying to have me help him with his iPod since I'm the one the house that has most experience with electronics in the family. BUT I don't understand what is wrong with his ipod. Here's what he is trying to do. He is trying to put his music from the device into my laptop. But when I connect the ipod with itunes it shows his ipod but doesn't show any of the music. It only shows Tabs that say Summary, music, movies, tv shows, podcasts, photos, and info. I can't find his music ANYWHERE. When I click on the music tab it just says sync and tells me if I do so all the music on the ipod will be deleted and replaced with the music on my itunes. I've been at this for almost a year. Anyone else encounter this?