Originally Posted by TBman
Like everyone has said, tough it through, but putting a capo on the 4th fret for instance to practice it makes it a bit easier due to the change in angle for the arm and the possible effect of a correction to the setup by the capo. Practice it on the 4th and work down to no capo over time.
If it is still hard after doing the above, your friend's guitar needs a setup.
As someone who is currently going through the barre chord learning process, I heartily agree with the above advice. Have them practice chord changes between C and F for several minutes a day. in a month or so, your muscles build up enough strength to hold the chords without the buzz.
I'm practicing using a I, vi, IV, V chord sequence in all the CAGED keys. This gives me a bit of practice with some common barre chords. For some reason the barre B really kicks my posterior more than the F did.
Pass on my sympathy to your friend. I feel his/her pain!