Ik put the music on offline mode. If i read your site, it should be possible that one pc can listen online and another device can listen offline. So i still don't understand. Also my native language is Flemish so use easy words 🙂 Thank you again.
In order to do what you want to, on your PC at home, choose the Spotify playlists you would like to be able to listen to while your husband works at the Bistro, and then right click them, and then select "Available Offline". Now, any of your playlists that are marked as available offline can be played in Offline mode while your husband streams from his bistro. Hope that helps! 🙂
Although, if the two of you stream music pretty frequently, I would strongly recommend buying another account so both of you have your own personal accounts and can stream freely.