Thank you for writing. I’m sure this is very upsetting to you. Please remember that you have nothing to be ashamed of. Your father has a history of inappropriate sexual behavior. You have probably become a target because you stopped him from abusing your mother. He retaliates by making you uncomfortable in your family home.
By confronting him directly, you were both courageous and generous. You gave him a chance to deal with the situation just between the two of you. Instead of apologizing and promising to stop staring, he tried to turn the problem onto you. This is not an honorable man.
Going for help for anxiety when you needed it does not mean that you are deficient. It means you are wise enough to get help when you need it.
You didn’t indicate why your mother has stayed with this man. She may be too dependent on him financially and emotionally to leave in spite of the way he has treated her. Telling her might give her the information she needs to finally separate from him. On the other hand, it might make things worse for her. I do not have enough information to advise you on this. You are in the position to look at the total situation and to assess what would be best. You might find it helpful to talk it over with a therapist if you can.
If you can’t get your father out of the house, then I suggest you see your mother and sister at your place or at a neutral place like a park or restaurant. You do not have to put up with his behavior just because others do.
I wish you well.