You don't unless you want to have legal proceedings taken against you
Call the police and tell them daughters boyfriend tried to kill her. They will take care of it.
can a mother put a restraing order on her 19 years old daughters boyfriend?
Threaten to dump him
If it doesn't involve her, stay out of it. If it does, threaten. What I mean by threaten is if he can't be honest, tell him you will leave him.
Dump your boyfriend and ask your mum what the hell she thinks she's doing dating her daughters boyfriend
No
yes
well it depends what she threaten you with and if he worth it.
Call the police and/or get a restraining order.
Is he the father?
Depends, what did he threaten him for?
Threaten to dump him unless he stops. IF he really loves you he should stop.