Huey hates being brushed but has no dislike of the brush itself. In fact, he likes to grab it and run off so I can't use it on him!
He can become a snarling monster while being brushed, but it is in direct relation to how many tangles he had.
A great help to me was buying a grooming table. That way I'm not trying to hold him with one hand...I can use that hand to hold the tangled area at the base to prevent pulling. Grooming is also accompanied by many kisses and treats (he gives me kisses, I give him treats)
You said your groomer threatened to muzzle Buddy? I would find a different groomer who will be patient and help with teaching him to stand still during grooming. A rough groomer or one who is in a hurry can undo any progress you make in a matter of minutes. I would "interview" any prospective groomer and see if you can schedule a double appointment window so they can take the time to get it done in a calm, unhurried manner. Good luck!