How does outside of a shove someone the back getting out of a car?
Rephrase the question, please.
Again, the friend doesn't deny that Brown and the cop got in a physical struggle while the cop was still seated in his vehicle. So the question is, what's more believable? That Brown shoved the officer back into the vehicle as he was trying to get out, or that the officer decided to latch onto Brown and pull him into the vehicle from a seated position? That just doesn't make any sense. Even if the officer was pissed and behaving irrationally, you don't grab a big dude from a seated position - you get out of your vehicle to assert your authoritay. So up to that point I believe the cop.
It also doesn't make sense why you shoot an unarmed assailant multiple times 35 feet away from you. So both stories are in doubt, but without more facts the best I can surmise is that Brown very stupidly attacked the cop, and the cop then very stupidly overreacted and shot a retreating Brown.