My Best friend has changed in a bad way??:(?

so i have a frnd who i guess WAS my best frnd b4,we used be gr8 frnds from the first grade,now im in 10th grd and iv shifted my house a little farther from his house,i mean he still talks to me on phone and even comes over for a nightstay sumtimes,likw when i got my ps3 he came over,but iv noticed some drastic changes in him,he is in bad company,he talks cursewords all the time,and once we were chatting with a girl,and he started saying things like(id **** her,id **** her anytime,yeah)he said these things,m so put off,and hes always rapping and cursing and talking abut fighting ppl tho hes skinny and i can beat him easily,i mean how can i convince him to breaK it up,i eman once i told him that i hate his personality and i dont like him anymore and he started saying things like(u made me cry,im hurt)but i am not like him,i hate ppl like him,how shud i break it up withut hurting him???plzzzz help:((((((