We always used to have the Flight Engineer ask the FO lots of questions, progressively getting more indepth, with the captain chiming in when he felt like it, usually when the FO was unsure or didn't know, (which was more often than you might think!), but the FEs were always aware that proticol assured that they never questioned the captain directly.
This went on for literally years of long distance flying, both miliary and civilian, and worked extremely well for all concerned.
I still miss that interaction and disemination of the experiences of some very experienced guys, with the FE not always the most knowledgeable on some subjects, usually the nav system.
Unfortunately those days are, at least for the present, not with us anymore...
Cheers