They can recover. I can't really tell from the pictures, but if they have any brown jelly disease I would at least give them a Lugols iodine dip. If so, be careful removing the corals for this dip so the brown jelly doesn't blow off and float around the tank, as I found it to be contagious. If it's just the picture and there's no BJD, then just wait it out.
Where are you keeping your alk
at? If it's above 7 and the corals have been fine in it for months, then I doubt this is your problem.
As for fragging the BN, just use wire cutters, nail clippers or some other tool to snip pieces off, taking care to not bring any dead parts with them. in some cases that tissue loss will be arrested with the separation.