This is a statement from Miller's lawyer. It clearly lays out what, at the very least, their story is. He also claims that Miller was not blocking the victim's car from the road and that he actually parked his car first, and then the victim pulled up on his car. He also says that is clearly shown on surveillance video.
If that last sentence is true, then I understand why Alabama isn't suspending him. Not to defend Miller, because I wouldn't be surprised if he knew more than what his attorney is letting on, but how can you kick him off the team if it's reasonable to believe he didn't know? It's pretty common for kids that grew up in tough neighborhoods to carry around a gun for protection, so even if he knew he was bringing Miles his gun it's reasonable to think it was just for protection.
There's no way of knowing for sure how much he knew that night, so for that reason I get why he's still on the team. That said, if I were an NBA team I would hire a handful of the best PIs I could get to look into his history, because I would be very leery about drafting him.