Since you are only applying for Global Entry which involves only the US (and not NEXUS which also involves Canada).. if I were you I would answer the question no if the only thing was that one incident..it's also a very easy thing to say "I forgot" about if asked as it's so meaningless... but they aren't even going to ask. Then next time you're in Canada.. clear it up with their officials like your brother did.

Of course it's just my opinion.. I'd take the chance..