If you live in NYC or near you can get a large selection of black licorice at Economy Candy on Rivington St. in the lower east side. You can also mail order it from them at their web site, http://www.economycandy.com/
Another good source for mail order with an even bigger selection of good imported licorice is Licorice International in Lincoln, Nebraska
FYI, this was originally a candy business in NYC that carried many types of imported licorice. When the owner finally retired, the present owners bought it and moved to Nebraska. I'd suggest that you call them and ask for their recommendation. My own suggestion would be to get a selection of six different types made up of Dutch and German selections. Each type has its own distinctive taste and your friend will certainly find several to their own liking. If you get salt licorice, don't get more than one. This is a real acquired taste.
or call: 1-800-Licorice (542-6742)