Gotta vent/ need advice (sorry it's long)

Okay, so I've been with my boyfriend for about 5 months now. It was a very rocky relationship, but we've been amazing lately. Anyways, he helped me with laundry last night and ended up going home at 12. I told him earlier tho if he has to go home early he can, he said it's fine that his uncle and aunt dont care what time he comes home. See he always days things like this, he made it seem like his guardians dont treat him well and want him at their place so I allow him to stay late so he doesnt have to deal with them. Anyways, this afternoon his uncle calls and asks to speak with my mom, I was very confused and concerned, I thought maybe I was in trouble and told them my mom was busy but I'll have her call once she was unoccupied. She really was and she did call back when she had time. And they told her that they had never allowed him to stay late and that they do worry and they never start the problems that he does. That he always talks back, doesn't try at school (I know this), is disrespectful and stubborn and fails to obey rules. They also said that when he would stay late he would say that he was running errands with my mom and that she will drop him. That's not true. They threaten to kick him out the house and he would just say that it's fine that'll I'll take him in and we'll get married and blah blah. I'm 17, hes 15 (nearly 16), I'm about to go to college, start my life and wont be held back by some kid who thinks life doesnt have rules. Turns out he also has a child service person on him to help his case to getpaper. He could get my mom in trouble and me in trouble. I'm so mad and disappointed and hurt bc he lied and made me think him as a hurt puppy when really he wasn't. I'm not quite sure what to do. Any advice? Thoughts?