The latest iOS beta app allows you to tell which family members are home and not. This is indicated at the top of the main timeline screen where the user avatars will jump between home and away. To use this feature you need to allow location data 'always' and set a location of your home. In the top left menu (under account settings) there is a switch to turn on location data, flick that on and make sure that your home has a proper location set in the home settings screen.
This is in beta and we would like to know how well it performs. We're happy if you would like to test it out and give us feedback on the performance. Let us know what you think of it.