My mum's boyfriend keeps hitting her and abusing her. What should I do?

Yes ring the police, she doesn't need to press charges , the police will....for assault and battery, straight to remand for a hearing before the court, 2 weeks maybe and then your mum puts a restraining order on him....that means he cannot come within a certain distance to your place or residence or even if he sees her in the street, he cannot approach her, no contact by mail or phone either!!

Tell a family member or ring the police

Ring the police.

if ur a male f4ck the goof up see how it feels to be hit I sure dont want to see my mother hurt I would be angry the first time I hear about it I'd go up to him and punch him out, if ur a female just call the police the only thing u can do and don't be concern what charges he'll get guys like that don't deserve a loyal woman they should be in prison rotting

Nothing will happen if your mum doesn't press charges. Try and encourage her to. Get advice from the link.

Inform the cops if worse