I'd recommend calling the GW's supervisor and posing the question to him. If his guy is writing tickets that don't pass court muster, he would be interested in stopping that practice.
Jeopardy has attached, so he's out of the woods on the charge so there is no harm in asking.
I'd bring up the other issues here regarding possession limits and such as well. That way, he can be prepared for the future. A phone call for some clarification could save him some heartache down the road.
Honestly, it doesn't sound like gathering that extra information would hinder your brother too much anyway.