Not knowing the laws in South Africa regarding abuse, I am not sure how I can counsel you. From your post, I am assuming that you are around 25 yrs old...is that correct? If so, you are no longer required to be in his home (are you in his home or is he in yours?). If you are in his home, you have every right to move out and be on your own. Do you have an income of your own? Are you able to support yourself?
No one should have to endure physical abuse. Here in the United States, it is against the law and in California, it is called "domestic violence". If there are similar laws in South Africa, then it might behoove you to take advantage of them.
For yourself, it would probably be beneficial for you to get some form of counseling, both for your lupus depression and for the abuse that you have had to endure from your father (both emotionally and physically).
You have taken one of the most important first steps, telling him that he can no longer abuse you and that you will no longer submit to his abuse. You must understand that it is NOT you who has the problem, there are some serious emotional issues going on with your father that HE needs to resolve. Until he does that, he can no longer take out his anger, unhappiness, resentment, or feelings of unworthiness on you!! Remove yourself from the situation, if you can, and seek treatment FOR YOURSELF. You father must help himself, you cannot do that for him. Your first priority is your safety and your well being.
Please keep us informed of what your decisions are and how you are doing.
Peace and Blessings