BIG blackpowder following at the Patapsco Ranges in Marriotsville. (
www.associatedgunclubs.org).
One of the clubs at the range is specifically a 'black powder club'. They hold many different types of shoots and the public can attend & participate in several of them. They have both Black Powder and Black Powder Cartridge events, all in all its a good place to learn.
Clubs he would be interested in:
-Gwynn Falls/Marriottsville Muzzle Loaders (MML), Inc. (they have informal quarterly shoots with training for new shooters).
-Tidewater Muzzle Loaders, Inc.
Both of these clubs have contact information at the link I supplied above.
MML has a public event comming up on the 12th of January and another on the 19th of Jan. Plenty of others comming up later in the year.