How to get a bad childhood memory out of my head

I was just wondering how I could possibly get rid of a past childhood memory.? It’s like I have ptsd from it and involves my older brother sexually abusing my little sister with disabilities and he had tried stuff with me but never let it happened. And then he would attack my sister when she was little and it currently happened until my mom caught him with my sister and he went to jail for awhile. But I keep having thoughts about what happened and sometimes it’s hard to go away. I can’t even trust my father with my 4month old WHOS a girl and it scares me to death because my mom and grandma always told me crap about him watching porn when I was a baby and my older brother would be upstairs watching. And I don’t even know anymore and need advice. Anything helps no negativity please