Music not playing on iTunes

Hello, everyone!

Yes, I have posted something like this before, but I never got any answers.

Using iTunes, I transferred music from CDs to a USB so my grandfather could play in his car. Alas, it's not playing in his car nor my mother's.

I put the songs onto the USB via Libraries, just like I do with my other songs which do end up working in the cars.

Also, I got a MacBook Pro yesterday and I checked the information about the files to see if that might be anything wrong. I compared it with a song of my mum's from her USB and everything was exactly the same, except the name of course, and what's under "More Info". My mum's song had information whereas my grandfather's had nothing except when it was last opened.

Also, my grandfather's songs aren't playing on iTunes.

Could anyone help?

Ta xx