Nickelodeon (ended 2001)
Haven't you seen the episode? Neither have I, but I saw a scene from it and it turns out Daggett fakes his death and Norbert is upset.
He's probably just joking to himself, all part of the love-hate relationship.
This may not be at all relevent on a board for a kid's show, but another example of this sort of thing is "Kenny vs. Spenny". The guys aren't brothers, but they also have a love-hate relationship. Despite being particularly cruel to each other on a regular basis, even insulting each other and enjoying each others pain. However, in the "Who's the better boxer" competition, the very cruel (and sometimes evil) one forfeited at the end because he did not want to seriously injure his friend.