teenager depressed?

after 5 years with his mother my son has come to live with me and my girlfriend . it was necessary because his mother couldnt cope with him . so far in about 8 months we've gone from being close to near hatred it seems . he's rude aggressive bone idle , typical teen some probably would say . he also steals lies , took an overdose , threatened my partner and has broke my nose . i'm at my wits end i love him to bits but how can i communicate with hiim when all he does is quote the poison his mother told him about me .
i want to help , i wasnt an angel at his age and i'd hate to see him repeat all my mistakes which he seems intent on doing
any suggestions gratefully received