Im not sure if this is the spirit of the question being asked, but I have booked FHR stays for both my parents and my wife when travelling without me, but I've given my wife and my dad supplementary plat cards on my account. So, there was no question of entitlement to FHR benefits, just that I booked it for them.
Although, the Shangri-La in Sydney didnt honor the benefits and claimed it wasnt an FHR reservation despite being confronted with the itinerary from the platinum travel service. We're still working that through customer service channels.