Boyfriends sons step dad

Okay so I've only been a girlfriend for like 2 months so do I have the right to get involved? My boyfriend has 3 kids from his ex 22 year old daughter, 19 year old daughter, 16 year old son. His son prefers staying with his mom but wants to move in with his dad. His dad was saying it's best to just wait until he's 18 to move in because he doesn't feel like going through court. So his son said okay. His son road his bike to my apartment because his dad wasn't home in tears. He said stuff been going on with his step dad. His step dad has been calling him a stupid fucker and worthless retarded pos. He has come between his relationship with his mom. He told his mom that doesn't feel comfortable with her hugging him anymore because he should be the only man she's hugging. So she stopped hugging him. His step dad found a condom in his room tonight and yelled at him saying "You think you're big shit you little manwhore! You nasty fuck! You're nothing but a nasty little manwhore and somebody is gonna make you their bitch someday!" He walked out and walked back in saying "Let's see it. Since you think you're big shit let's see what you're packing you nasty fucking manwhore". And attempted to pull his pants down. He tried to get away and his step dad held him down until he kicked him hard in the balls(and he's a soccer player). Then got his bike, went to his dad, and then came here when he realized he wasn't home. And it was raining. His dad is out with friends because this is his Friday so he's not answering. Should I confront his mother or is that too much because of how long we've been together?