My father has been mentally and economically abusing my mother for years now. She was a stay-home mom and he tracked all of the money she spent, complaining when she spent too much on food, not allowing her to do anything with "his money", she had to basically be his personal secretary. He constantly mentally abused her saying she was nothing and didn't have work and that she needed to pay right away for their 14+ years of marriage since all this time he had been the one paying and none of the money he spent on us was "fair". When she tried to set up a job and managed to get a funding from her family he tried to force her to start paying half of the family costs (rent, expenses, etc.). If she did so she would not have had enough money to start the business and my father knew that, he didn't care about that he just wanted as much money as possible (it was NOT her money, it was a bank loan her parents had made). He also told my mother that if they divorced there would be no way for her to take or see us, her children. He refused to pay any child support and demanded that SHE pay for the past 14+ years. My mother finally could not take it anymore after fighting for a very very long and messy time and she left the house and country to go back to her home. They are not legally divorced but have been living separately for around 3 months now and are not sending any money to each other (my mother does not have any money to send but he insists that she does). My mother did not take any money (she even took the old broken suitcase because my father would have called her a thief if she took a new one). Her plane ticket was bought for her by her sister. 

I'm 17 and my sister's 12 and we basically do everything now. My father still fights constantly with us and mentally abuses us as well, picklocking my sister's door and saying that everything in the house is his, yelling at us when we don't do what he wants, constantly talking badly about my mother and calling us thieves and liars (this is what he always repeats and repeats when we argue). He also constantly complains that my mother should send child support.

My mother is trying to bring us to her for this christmas break, for just 3 weeks. She does not have a job or any form of income yet, she has been living at our aunt's house and searching for a job that pays enough to bring us in, she's currently going under training. With loans and borrowed money she has managed to buy me and my sister plane tickets (it's an oversea trip and costs over 2000 euro total, my father refused to pay a cent). 

This is us visiting our mother. Don't we have the right to do this? I have tried 3 times over the course of the past 2 weeks to talk to my father and ask for him to drive us to the airport, that is all he needs to do. But he always yells and claims that "you three" (he always says this, as if we leave him out on everything and he HAS to be part of everything) are going to spend Christmas together at our home country, and he's just generally bitter. He says it's our fault for not asking for permission, but how can I when he yells me down like that every time? He's not even paying for the trip, he actually expects my mother to pay for him too. 

Today he has said that I should be held responsabile for my self-decided actions that I didn't tell him about (again, I told him 3 times but he always just said what he wants) and has told me for the nth time to leave and not come back. 

I don't care if he doesn't want me. I don't need him to love me or care for me. But I'm in high school and my sister is in middle school and she has to finish here and she is scared of him. He already cuts off our internet and takes us out of school to run his errands. He always complains about having to support us and openly shows he did not want this. He is always irritable and always picks a fight. 

Even if I want to avoid conflict, my mother has already bought the tickets and I very much want to go see her. I will find a way to get me and my sister all the way from the small city we are in to the big city's airport, a 2+ hour drive. We will return at midnight to the big city on the return flight but if my father will not be there to pick us up, I'm not sure what to do. I don't have any money except the 100 euro my mom left with me for emergencies, so I'll try to cover me and my sister's trip expenses with that. 

However, when we return and he does not intend to financially support us anymore, what should I do? Should I contact the police now, in advance? Should I ask for help at school? My sister has been pushed into depression by this and it's very hard on me to live like this too. 

I haven't told anyone yet but I intend to call a domestic abuse centre for a meeting and advice. There are 2 weeks left until we leave.