Brobocop is a combination of the word 'bro' and 'robocop'. It is used to refer to a 'bro' that is always checking up on you and making sure you follow the rules.
Peter wouldn't let me smoke weed, he's such a brobocop
It is in no way a positive nor negative term. In times of utter disgust when discipline is essential but friendships must stay in tact, providing guidance for a fellow "bro."