MMJ is an abbreviation for Medical Marijuana.
As for a contact to get a guest for the show, go to their website and look for their contacts list.
When I used to write for MMJ the then CEO of CNBX would reply to me personally at times. Those days may be way gone, but I would think they will advise who will do a call-in, etc.
Good luck and please let us know if your friend is interested and vice versa if CNBX is interested.
Take care, Jim