Please remember that Business Calendar uses the sync of the Android calendar. Therefore, only what can be synced with the Stock calendar also syncs with Business Calendar. Normally the Facebook-app itself establishes the synchronization with Facebook. Therefore neither our app nor the Android OS are responsible for the sync with Facebook. What you could do is to re-log in with the Facebook account hoping that it will update the in formation in BC. Some of our users also integrate the FB calendar in Google Web Calendar and sync the FB events via Google. Please note, that those events are usually synced las read-only entries and it is not possible to influence such calendar in any way.

You can sync your Facebook events via an ical link, like I do.