Realtionship advice about how to deal or break off a toxic relationship with my father?

I am a 26 year old woman. I have a very difficult relationship with my father which seems to go back and forth and is upsetting my life during important periods that matter most. I am really sick and tired of this vicious circle and its draining my energy when I need it most which leads to depression.
My father was abusive physically with my mother and emotionally with me and my brother. I am the older daughter and being a girl I feel the abuse was more directed towards me. My brother has cut off all contact with my father for some years now after my mother's death. I am still in touch but I find myself very agitated after every conversation. But I still don't feel like completely losing touch with him at the same time I feel that I should for many things. Although my father is abusive and inconsistent. He seems to care about what happens to his children and offers to help which he does inconsistently and conditionally. I feel that he is insecure about us leaving him and severing all ties which my brother did successfully, but it is this insecurity that makes him treat us badly by pulling the rug from underneath our feet when we need it most.
For example, I feel it is this insecurity that made him move to a different country when I was in the turning point in my life of standing up on my own two feet by getting a degree. He forced us to move, which made me repeat two years for no reason because of hostile tax laws of the host country. When I eventually started in university after my mother's death, delayed unnessarily by two years and when I was in final year of my university, he refused to pay the fees, which led me to break down and lose another year. I fought through this by borrowing money from other sources and got my degree. I worked for sometime and now I want to embark on a post grad. But although he seems to want support me financially, he seems to play a lot of mind games which really confuses me I don't know what to expect and what causes his mood and thoughts to be so unbalanced which in turn is adversely affecting my decisions and life because I feel like I am living on an edge. Having lost so much time unnecesarily has really affected my career and financial standing. I also feel like he is doing this to make sure I am forever dependent on him. It feels like he does this constantly and is very manipulative in winning back my affection by showing a good display of how he cares, simply put he would be doing certain things to help me out and when it matters most or when it is almost time to achieve he gets cold feet and withdraws with abusive remarks and no contact. I realize this relationship is toxic, but I am at a loss of how to sever it altogether and what will be the consequenses for me if I do drop all contact.
I would be greatful if you could advise me on what is the best course of action for my mental wellbeing and progression in life. Even if you suggest break all ties, how seems to be the burning question. This erratic relationship with my father has held me back an awful lot throughout life but especially the past 10 years.
Kind Regards,
Confused and upset

There is nothing you can do to change your father but you can change how you deal with him. When a person thinks and behaves erratically, they are very frustrating to deal with because your expectations are never met and it becomes an ongoing disappointment. You need to adjust your expectations.

Try developing the attitude of, "That's just the way he is." Listen to what he says but don't get pulled into arguments and most important, don't ask him for anything, financial or otherwise. Pay no attention to promises. If he comes through for you, be thankful but neither ask nor expect anything from him.

If you can get rid of your expectations, you can stay in contact with him without the emotional toll it is taking on you.

nobody wants to lose their father, or their sense of belonging in a family, so its a very tricky situation. it is a bit unfair that an abuser can put you in a situation where you need to choose between the emotional distress of having to tolerate the continued presence of your abuser in your life, or the emotional alienation of essentially dismissing or disowning your family structure. however, people's parents do eventually die, and we seem to be made to be able to deal with that most of the time, so eventualy everyone loses their nuclear family structure. it will always be a bit of a problem though, so if you work out a way of dealing with it that is good enough, don't assume that there's got to be some other way thats going to be perfect. however, with victims of trauma, it is often the more difficult task to realize when a setup is definately not good enough. make the moves that life demands of you, to be yourself, as the moments come. there is no simple answer.

You mention that your brother has cut all contact with your father...I am wondering how your brother is holding up after this?Okay,from what I have read here...it sounds like father uses money as a control tactic.Some people do this especially when they know you are in a position where you need them for support in any way.The upsetting part is how he stops and has no contact when you need him the most...through those monumental times in your life where you are left to take steps backwards,rather then forward.
Losing touch with a parent I would expect is very difficult,some people can and some people can't.What I am thinking here are two different things.1.Do not expect anything from him,automatically know that when you need him the most he isn't there for you and continue a relationship with him or 2.Accept that he is toxic for you,live completely dependent upon yourself without him in your life.