While Brian was hanging on the street next to Roman's cab depot, high on cocaine, he met Niko Bellic, eventually giving him 100 dollars, after making fun of Niko's accent. This encounter is meant more of an introduction to random character missions than an actual mission.
Niko later encounters him at another spot in Hove Beach, around the corner from the Hove Beach Safehouse. This time Brian asks to be driven to visit some crack dealers to buy the "biggest rock in the world". Do not use a police car to drive him. If you do once you get to the location it will tell you "The deal was disrupted by police presence" The deal goes well, and Niko drops Brian off. When Brian is in a car, his hat gets removed and it is revealed he has a "High and Tight" hairstyle.
A week later, Brian meets Niko a third and final time, and relates his story -- his situation deteriorated after their last meeting (he had spent some time as a crack whore), but he is now on a nine-step recovery program for his habit, and is engaged to be married. He tells Niko he is now at step nine of his program, in which he must speak to some of the people he harmed and ask them to forgive and forget -- he apologizes for his rudeness when he first met Niko, and explains that he wants to pay back some of the former dealers he owes money to. Niko forgives him and agrees to drive Brian to their location; the dealers, however, are none too happy with Brian, and attack him -- Niko can kill them to save Brian or simply point a gun at them to scare them off, and then drives him home.
Brian is never seen again, but it's suggested he stopped using drugs and got married.
