My mother's attitude towards my stuttering (she hates it so I hate myself lmao),

My mother's attitude towards my stuttering (she hates it so I hate myself lmao), Not even ten minutes into me having dinner with mum and grandad, I stuttered on saying grandad and she mimicked it. Then she looked like a naughty child, amused but very fucking aware she said something she shouldn't have done. She was kind of drunk and I was still in a good mood so I just ignored it, but I worry that made it seem like it's okay (despite how I've told her that's not helpful before but it doesn't change her behaviour at all) but she's said she does it to make me aware? Of course I'm aware Karen lmao (ironically, that is her actual name) but ofc I'm aware, I'm not deaf so I can hear what I'm doing????? Would anyone believe me if I said this fucking bully works for the NHS. It's laughable, she's actually so pathetic for this