Pearls of Wisdom? Hmm... would nuggets of dubious experience work? I'm not sure if I have any of the former.
Careers are mostly teaching, but also Museum Curatorship, writing (Tony Horwitz is an example of a history writer), and public history. Advising is another possibility, but I'm not aware of anyone who has made a career of it. But one might ask, "Advising what/who?" Well, video game companies often need historians (I can guarantee you that there was at least one historian, probably more, working on all the Call of Duty games). History (and the historical method) is a skill that actually translates well into almost any conceivable profession; the problem just comes in convincing people of it (people underestimate the importance of history all too often).
Your brother might want to look into getting a copy of
Becoming a Historian: A Survival Manual. It might be available at a library, but I doubt it. Chances are he'll need to order it from the AHA (American Historical Association, not to be confused with the American Heart Association).
Um... actually, my response is getting pretty long. I'll send you a PM with more, so as to not hijack the thread with my hi-jinks.