For information....
In some cases, bluetooth audio may work.... the FreeBSD handbook is not totally false, but may be incomplete
Base system can associate devices, but it requires an additional audio "firmware layer"
This firmware layer is included in
audio/virtual_oss
I haven't personally tried, but from what I have read this is working, and it seems that even under Linux, bluetooth audio is handled by 'virtual_oss'
I don't know if it supports high definition audio, but basic audio can work
To setup 'virtual_oss' you should find help on Google
Anyway.... there is no real support of Bluetooth in FreeBSD, and this isn't a priority.
The current support is very basic, through 'netgraph' modules.
Netgraph modules are intended first to create/manage virtual network devices (for advanced users)
This is not basically the goal of Netgraph to manage bluetooth... so I always found that strange and "wobbly". It seems to be more a "workaround solution" or "quick and dirty job" for just a basic support for keyboard and mouse.
According to me, there is no guaranty for the future regarding the support of bluetooth in FreeBSD.