Can HomePod stream Fios channels to other TV's?

You can go from a streaming device or other AirPlay 2 enabled device to a HomePod but not the other way around. I’m not sure what fios tv is! There are a number of Apps or possibly an fios app that let you use your cable Provider login credentials to view the App. My cable provider doesn’t have an app for Apple TV but does for iPad and iPhone. I watch it via web browser from my MacBook and airplay the sound to HomePods. I otherwise could AirPlay the channels from my iOS device to Apple TV if I wanted.

Without an Apple TV or other set top boxes your tv would need to have Airplay 2 capability to stream to. It might not send sound to HomePods though, it would be best to airplay to an Apple TV that you’ve connected to HomePods.

However anything you watch on Apple TV box can airplay the audio to HomePods. For an Apple TV 4K you can set the default audio to your HomePod.

You can only get your cable subscription on Apple TV as described above. Looks like there is an app. Go to the App Store on your Apple TV to install

homepods can't stream to! other devices

they can be streamed to by ios devices or from computers or an appletv box

and they can stream from the internet services they themselves can access by void commands like

(apple music, and tunein radio and such)