I've seen first hand what happens when an alcoholic stops drinking without medical supervision, there's a reason they told her to keep drinking. My A had a seizure at exactly 48 hours post stopping. Had I known that was a possibility I wouldn't have thought he could stop all on his own.
Cardiac arrest is also a possibility.
Just be there for your friend when they get out of detox if you are comfortable being there. If not, then take some space. You can control you and no one else.