Do you think my mum has anger problems and suffering from depression?

My whole life my mum has been distant, she's never said I love you or cuddled me in any way, she doent show any emotion at all to anyone, She lashes out at nothing swearing and shouting at my step dad saying awful things, if you ask her if she's ok, she says that your a bully and stresses out. For example we were sitting watching tv and she started shouting and swearing very aggressively at my sister that she was eating to loud, she sends my step dad to bed and he just goes, I,ve walked in on her shouting at him and heard somethings which of course she didnt want me to hear because she shut up straight away and started acting nice. Now my mum and step dad are in the middle of seperating because she says she hates hims when hes a wonderfull man, she cant cope alone I asked her to see a doctor and she says I'm being stupid. I know she sounds horrible but I love my mum and she does love me she just cant show it. How can I help her if she doesnt think theres nothing wrong. help