ummm, do you have a way to post a pic? This might help us diagnose it better. Also I wouldn't cut the whisker. If you cut it in the wrong spot it wont grow back and you may injure the fish more than it already is. I can take an educated guess if you can get a good shot of what you are talking about.
It's one of his mental barbels? The ones on his chin? I would just leave it unless it really bothers you then you can for sure cut it just behind the bend. It may stay like this if you don't. I personally wouldn't cut it cause it is not harming the fish. Some people are ocd about their fish though lol. If you do cut it sterilize whatever you cut it with and add a lil salt to your tank for a treament to stave off infection since you are slicing into the catfish. Won't take very long to grow back either.
same thing applies. Just don't cut it back too far if you do it. The top ones are referred to as the Maxillary barbels. There is a bone at the base where it attaches to the skull. If you cut too close to that it will not grow back. So I would just go right behind the bend if thats what you choose to do.
The pic is kind of blurry so I want to make sure of something. Is it just bent or is it curling? If it is curling you have water quality issues. Early stages of find and tail rot manifest in catfish as the whiskers degrade first then the fins start. Just trying to make sure this is your only issue is a bent whisker and not something more drastic.
I'd leave it alone. He will go through many sets of barbels in his life. They keep getting injured, broken, disfigured (less often) and keep growing back (unless an infection sets in like mouth/barbell rot that may destroy the base of the barbell).
Chin barbels are called mandibular. Upper jaw main barbels are called maxillary.