Am I wrong? Baby related

Long but please read. I have never met my boyfriends mom in the years we have been together because he’s always told me stories about her and she is a very toxic person. He is 19. She gets upset because he won’t stay at her house and watch his little brother. Then, she resorts to getting into his truck and taking all of his items throwing them onto the floor and calling him all kinds of names including, “a piece of shit,” “a boy who will always be like his dad,” “little bitch,” and the list goes on and on. She gets mad over little things and blows up with physical violence, throwing things, cussing, and screaming. Well today, he was with her and she got upset because he said he would like to come into town earlier because he had important business here. (They work together 2 hours out of town and car pool but she won’t let him come back to town until about 6 pm because shes with her boyfriend). He’s tried driving himself and when he does she gets into his truck like I said and will even take his key and leave. She asked what kind of important stuff and he said “you have a grandson on the way and if you don’t clean up you’re act I don’t want you around him.” And she punched him in his nose. He got out of the car and she drove off, leaving him walking for an hour. She came back and started screaming at him to get in the car, throwing things at him. He gets back in and she throws a towel at his face and told him to clean his nose. The whole time she cussed and called him names. He comes home, his face was covered in blood and he told me what happened. She later calls him telling him she’s an hour away, ran out of gas, and needs money. He goes to help her and she started calling him names and saying things like “ I don’t even know why you have a girlfriend when you can’t treat your mom right.” She tells him to go pump and pay for the gas, he does and she calls him a bitch when he gets out. She then tells him that he’s not doing it right and rips the key out of ignition breaking it. She gets out the car, kicks his penis and threw the gas can at him. He just told her he doesn’t want her or our son in her life and she said good. Keep in mind, we both have jobs, live on our own, and are in college. Yes, we are young and pregnant but we don’t rely on anyone else. Am I wrong for never meeting his mom and never wanting to? I’m bipolar and I would just rather not put myself into a negative, toxic, environment that could set me off. Also, am I wrong for never wanting her around my son? I haven’t wanted her to meet him since the day I found out i was pregnant. My boyfriend had mixed emotions about it because somedays she was good and others not so much. Even if she does change, I don’t think I want her around my son. Is that wrong? This is very hard for me because I’ve always been extremely family orientated and valued a good relationship with my significant others family. I don’t want to deprive my son of a whole family but I don’t think he should be around that. I feel so sorry for my boyfriend, he goes out of his way for his mom and he’s treated so badly. It’s not even just him, she thought her boyfriend was cheating so she got on a hoody, out a bandana over her mouth, and put her gun are her waist and walked around his house to make sure he wasn’t cheating