I think that all the State has to do to prove that it was not self defense is to play the 911 tape. He did get a break on the burden of proof. But it is not as big as it seems because the State still has to prove that it was not self defense. Time will tell. I still believe he needs to start getting his affairs in order.
I would advise him to get his affairs in order in any case. However, even playing the 911 tape may only lead to reasonable doubt and not beyond it. As others have said, he was outnumbered, 3 to 1. He may have feared for his life.