An aide-de-camp was, generally-speaking, an officer in a military force or organization who was the idiot-boy (or girl) for a high-ranking general, admiral, or other military official. Another way of putting it was that, anyone who was "selected" to become an officer's aide-de-camp had become, in effect, that officer's bitch. Such an unfortunate being could be subject to any and all sorts of humiliations.
On the flip side, some officers were known to practice nepotism, and appoint members of their own family to be their aide-de-camp. No such aide was ever trusted with anything vital, of course, but occasionally one did develop enough initiative to make a difference. Such persons were usually either killed or promoted; rarely, neither option was appropriate, and the former aide-de-camp would be given their own command within the regular forces.
Some aides, despite their gross incompetence, were allowed to retire from military life. Such was the case with Captain Sillybollocks.