So, Danny takes Matt's words seriously, and consequently pretends to be Daredevil while protecting Hell's Kitchen.
Brett discovers that something is wrong with Daredevil when he does not specifically leave the delinquents to 'Officer Brett Mahoney' as he had done until now, and later, when he does not recognize him when he meets him one of those nights.
Maybe angst when he realizes that this Daredevil is not the one he knows? Probably knowing that something has happened to him.
Danny pretends to be DD, Brett knows something is very wrong
Brett discovers that something is wrong with Daredevil when he does not specifically leave the delinquents to 'Officer Brett Mahoney' as he had done until now, and later, when he does not recognize him when he meets him one of those nights.
Maybe angst when he realizes that this Daredevil is not the one he knows? Probably knowing that something has happened to him.