FeedItem should show to Chatter FreeUser

When case is created from partner Community User(Partner Communtity Profile), I'm creating record in FeedItem,

FeedItem fi = new FeedItem();
         fi.Body = 'Feed Body';
         fi.ParentId = '5003000000D8cuI';
         fi.Visibility = 'AllUsers';
         fi.NetworkScope = 'AllNetworks';
Insert fi;

Now i want this feed to be shown to Chatter Free User who is having "Chatter Free License".

How can i show this Feed to ChatterUser? Any Approaches/Workarounds.