The crazy glue and charcoal fixes aren't generally more than temporarily successful. For the most part, they fall off very easily. They just don't bond to Vulcanite very well. The kind of fix you would need to make there is one that would be likely to fall off at some point.
Unfortunately it might fall apart sooner or later. Hopefully later. It’s like ceramic fills in molars. But maybe it takes some time and some hours of smoking. If it fails you can do another fill or think of a replacement stem.