moms with teenage kids incarcerated or facing prison

My 16 yr. Old son is accused of shooting and killing a community hero.he was snuck into a16 yr.old girls home and confronted by an enraged foster father who became physically abusive and requested that his wife bring him his handcuffs and gun.somehow during his physical assaults on my son in fear for his.own life my son managed to escape the man and thehome but is now being charged with murder. I am scared out of my mind for what could possibly be his fate...A good boy who's never been in,any kind of trouble with the law or otherwise, good student in school works p.t. Making legitimate money and he's incarcerated and i feel so powerless. How do i handle this fear, loneliness,grief? Please help me with any kind of advice. Thanks!