About all you can do is help him locate and pay for an attorney to take his appeal. Unfortunately for your friend, the time to challenge evidence is during the trial. Even if they lost the objection, they might have had grounds to appeal. As it stands, after three years, he will likely need some compelling evidence of incompetent counsel or serious malfeasance on the part of the prosecution or investigating law enforcement officers to get a new hearing on the matter.
Though I seriously doubt that the video will prove what you hope it will prove. Many lay people think that something will prove innocence when it will not, in fact, do so.
Understand that being an accomplice in a homicide can put you at the SAME RISK as the shooter himself. So, all because he may not have done the shooting, if he drove the car and the state can manage to show (and they apparently did) that he knew or reasonably should have known the murder was going to take place, then he's just as guilty. Alternatively, if he was charged and convicted of a lesser offense but had such a significant record as to justify an enhancement to life, then he'd still be where he is.
But, if you want to help him, about all you can do is help him find an attorney to review his case.
