Hello, I'd like to help you with your question.
What you have gone through with your parent's biological son is extremely traumatizing. And each time your parents invite you to his home or bring him up in conversation, it is opening those wounds and making you relive what you had to go through.
Right now, it sounds like you have no yet had the chance to work through much of your pain and find new ways to cope with what you survived as a child. No one should expect you to be ready to talk about your parent's son or to associate with him now, if ever. Try to think of it this way- if he had been a stranger and had done this to you, no one would expect you to associate with him in any way. That does not change just because you are part of this family. You still deserve the right to be protected from him and what he did
For some reason, however, your parents are not respecting your feelings. It could be due to their own shame over not protecting you, or their own inability to cope with what happened or that their son could be capable of hurting someone like he hurt you. Either way, their actions with you are more about what they feel than what you need right now. You do not need to forgive him just for their sake or even for his. This is not about their needs or his needs. It is about you. You need time to heal and help yourself through this difficult time.
If you find that being around your parents is too difficult for now and they will not listen to your requests to stop bringing up their son, it is fine to let them know that if they continue to mention him, you will either need to leave or otherwise end your conversation with them. Then follow through. As soon as they bring him up, leave the room, home or end the conversation. You do not have to be mean to them. Just tell them "I need to go". Then leave. This helps you gain control over the situation and protect yourself at the same time. And it also may help them to realize that they need to stop bringing him up.
If you feel that your parent's son might still be hurting other girls or women, you may want to try contacting the police and/or an attorney to see if you can report what you suspect. It never hurts to check into the situation. However, you may want to try to have support while you do this from an understanding friend, family member or even wait until you being therapy so you they can be there for you. You should not have to face this situation alone.
You can also work on how you feel through self help. Learning about the effects of trauma and gaining support through on line forums and other resources can help you work through your trauma. Here are some resources to help you:
Healing from the Trauma of Childhood Sexual Abuse: The Journey for Women by Karen A. Duncan
The Wounded Heart: Hope for Adult Victims of Childhood Sexual Abuse by Dan B Allender
I hope this has helped you,
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