Terry's points are well made.
Your friend has 7 days from the original JC before the DF is announced. During that time your friend can tell the elders that he wants to appeal. Some more fairly local elders, probably from a neighboring congregation, will handle the appeal. If your friend's "presentation" is perfect, he's 100% repentant and/or denies the charge and they don't have good enough evidence, he might prevail. Most of the time, local appeals don't work though. The JC that ordered the DF, will likely be involved in selecting who the appeal committee will be. In that process, they will color the appeal committee's opinion ahead of time.
I am aware of a DFing that was "rescinded". The person was announced as DFed and then began written correspondence with the Branch. It took several months, but eventually the branch told the elders to announce that the "Disfellowhipping of Joe Blow has been rescinded".
Oh to have a video of all the WTF?!? looks on the congo's faces.
om
(pm me if you want more details)