I'm looking at doing some of my really old kirby brush rolls.
From what I can see the bristles are held in with a U shaped piece of thick wire/ metal in holes in the wooden brush roll.
If I can pull them out, then I can re-bristle them easy enough.
Placing new bristle between the prongs of the U and forcing the U back into the wood of the brush roll should make the bristles stand upright. Then after a trim, as good as new... In theory...
I'm not sure about your compact brush roll. How are the bristles held in place?