I think his best bet is a plea to manslaughter or something like that. Because he was 17,I think he has to be offered parole, even if it's something like 40 year to life.
Someone mentioned,Imagine a family member is a high school student. One kid says something bad and lightly pushes the other person. He proceeds to shoot or stab them, how is that self defense and not excessive. It such bs that it a matter of race.