He's definitely going to have a hard time.
1. He shoots the unarmed kid rather than the one with the gun
2. He chases after the armed kid and fires shots down the street
3. He comes back after 15 seconds (a really long time in this situation), acquires another firearm, and puts five more rounds in the kid who has been down the entire time, who is still down, and who he has to almost step over to get to his second gun
4. He lied to police
Any one of those things could have flown, but taken together, they show a man who was unsure of his target and was careless in his shooting; had the time and presence of mind to pursue the felon after the threat was neutralized and engage in further careless shooting; and finally had the time and presence of mind to return to the scene, acquire a second weapon, and shoot the already unconscious accomplice.
At no time within this frame does he pick up the phone to call 911, and when police do respond, he lies.
All this just really stacks up against him.
Appalling as this all is, the family's reactions to the verdict were just as bad. The family(I assume of the dead boy) are shown in another vid, jumping and cheering and hugging each other. Yeah, your kid tries to rob a store and you're elated that his murderer is punished. There's something wrong with your priorities there.