This section of the guide to Marvel's Spider-Man contains a breakdown of the "College Buddies" side quest.
Mission's starting location: Greenwich
Reward: 1500 XP.
Talk to Philip Chang, to learn that his buddy went missing. The only hint is the picture of the location, in which the man went missing - he was wounded. You will also learn that the target is in the financial district.
The search might take a while - go to the location shown on the screen above. Approach the burning building and a cut scene will commence. You will have to fight a group of demons. The fight isn't very difficult - after finishing it, you will find Carlos, and the mission will be concluded.