Advice Please

My boyfriend and I have known each other for 20 years but have been dating for a little over a year so we know each other pretty well. We lived 3 hours apart so after a year he asked me to move in with him and I said yes. The problem isn’t us, it’s his 19 year old son that also lives there. He doesn’t work, doesn’t pick up after himself and just smokes weed all day. He had a job for 3 weeks and quit because he had to clean the toilet. He leaves a mess everywhere he goes so I’m constantly picking up after him. I’m not asking him to dust or mop, just if you get something out put it back up. I’ve asked this on many occasions and it’s met with deaf ears. Come to find out he has quite a bit of a temper. Him and his dad are always arguing and 2 weeks ago it got really bad. His 15 year old that we get on the weekends was just sitting there and he started calling him names and his dad told him to stop. He proceeded to call his dad names and I said ‘hey that’s enough’. He started calling me names and threw a frisbee at me while I was walking down the hallway and his dad stopped him from coming any farther. He then hit his dad and went after his brother. All of this for no reason. He’s gotten angry before but nothing like this. His dad kept telling him to get out but he just continued. Finally he left. His dad has had custody of him since he was 6 and the mother shows up every now and then but he can’t live with her because her boyfriend doesn’t like him. He apologized like a week later but has gone off a few times since then, nothing like that time tho. He has no consequences so he keeps doing it. What can you do besides forcefully kicking him out and I don’t see that happening. It’s like walking on eggshells around him hoping you don’t say the wrong thing. I’ve told my boyfriend that I don’t feel safe or comfortable anymore and he begged me not to leave him. We do love each other very much and I don’t know what to do.