If you family has been BKs for 20 years, am I correct in saying you are more than 21 years old?
If so, you are an adults and your rights are protected by law.
I appreciate that what you are speaking about are familial or paternal pressures but it is good to remember that you are a human being and have human rights of your own. If you have grown up in a world that is completely defined by the BKs and a dominating Father, perhaps you don't have a strong personal identity and an idea of a "boundary" between who and what you are, and who they want you to do.
First and foremost, there is nothing within BKism to allow your Father to do so. It goes against BKism because BKism is either a matter of personal choice, or destiny. If it is not your choice or destiny, then he cannot force you. Fullstop.
Perhaps one way would be to have the courage to ask the centre-in-charge the question, in front of your Father. This will take courage, I accept, but it should also silence your Father. If you ask the centre-in-charge, does your Father have the right to force you, or is it correct according to Shrimat then the accurate answer is no. If the centre-in-charge admits that is Shrimat, then your Father must remain silent about your choice.
Would that work?
I also appreciate it is very easy for us to sit here and make a suggest that would throw your home into turmoil. It is amazing how nasty and difficult BKs can become for all their "positive thinking" and "purity". It is also very difficult for us to give advice without knowing more about your circumstances. But I can re-assure you that your Father has no right to be doing what he is doing.
Can you go and live elsewhere? With other family members or on your own? Or do you want to stay at home.
If you have grown up as a child within a BK family, it is likely that you have been manipulated in many way and have not developed a healthy self-esteem or world view.
How was your experience and what makes you feel so strongly that BKism is not for you?
Thank you for posting.