I have severe hearing loss (if "Widex" is familiar name in your house, you'll understand). I find 2 types of Bluetooth headsets that work well for me, but only one in very noisy environments.
The Motorola 720 is the external type. A hook hangs over the ear, but the speaker sits ON the ear. If the environment is normal, the headset performs pretty well. It's also almost the only kind to use if you wear a hearing aid.
For noisy environments, I prefer my Jabra BT-210 (which has been replaced by the BT-500) headset. It has a piece that goes into the ear. If it's adjusted right (by the user), it's almost too loud. But you can't use it in the same ear as a hearing aid.
If he does wear an aid, there are aids that have built-in Bluetooth, so they function as Bluetooth headsets for the phone as well as hearing aids.
Both the Motorola and the Jabra have good outgoing sound - people can hear me with very little problem (unless I'm on the interstate and the window is open, but that's understandable).
Samsung has what I'd call decent voice control. Not great but, with a little experience, usable. The only really great voice control is my wife - she understands me a lot more often than my Samsung phones do.
