family sharing on Apple TV box

Hi. I use Apple TV a lot and wanted to share my movies with my son who lives at a different address. I bought him an Apple TV box expecting to be able to share my itunes library with him but we're having trouble working out how to do this - it seems family sharing with family at a different address can be done via iphone, ipad, and mac, but not Apple TV... Is this correct or are we missing something somewhere? Thanks