I’m sorry your mother is such a bitch. If I was you I’d try to explain to your mother that stuttering is a spectrum, some people have a mild form (such as your brother) and others have a severe stutter that can only be managed much like a condition. If she doesn’t understand that or care to I’m really sorry. Stuttering and anxiety go hand in hand so if your mother is a source of anxiety I’m not saying cut her off but maybe she’s not a person you should rely on or look to. I know I’m just an internet stranger But if you ever want to talk or need to you can message me.