<human>: Can you provide a brief rundown of the text in within 3 sentences?

She constantly blows up at anything, she screams at the top of her lungs at everyone at the flip of a switch. She goes from smiling to snarling so quickly at things. Was at a restaurant and was bitching about some guy on the other side that was "staring at her". She constantly -screams- at her 16 month old child. I have tried to talk to her, our parents have tried and nothing has helped. What can we do to force her to get help? Im worried she is going to flip out at the wrong person and end up in the hospital or worse.
<bot>: Sister flips her moods like a light switch, family all worried about her; She wont willingly get help. What do?