I am in search of answers fairly quickly. My son has a friend that is 16 and his mother has kicked him out of her home

, He came by and asked if he could move in with us, I do not have a problem with it, but his mother is "Mental"

tonight she called looing for him (he's not here) and said she was going to call the police. This boy is a very good boy and has every intention of graduating high school and future plans to join the Military. His mother is mental unstable, and uses drugs to feel "better", she says tells him he is no good, and says things to him that a child just shouldn't have to shoulder.
We live in SC and I know he can legally move out of her home when he turns 17, but what can I do in the meantime to help this boy? Can he move in with us, work, and be safe with out repremand? I don't want to see this boy end up on the streets, and on drugs like so many others in this town have.
What can I do leaglly for him?
Thanks for any info