Maximohs -
This is DEFINATELY emotional abuse and there is also physical abuse if she is hitting you. Does your dad know what she does to you? Sounds like he doesn't know how to care for you either.
I can understand why you are not sleeping - if someone was threatenting to kill me I would sleep with one eye open too.
I don't know how things are in Norway - is there a state agency that takes care of children who are abused? In the US they generally call it something like DCYF (Department for children, youth, and families).
You need to run to one of these places if it is available to you and get help for you and your brothers. If it isn't available, tell another adult, a teacher, a doctor, someone and see if you can get some help.
Tranquility
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