Friendship Drama

Friend A called me randomly one day and told me about his time with friend B about 2-3 years ago. He said she abused him emotionally and doesn't want the same thing to happen to me. He said friend B stole things, wouldn't clean up, and threatened to kick him out. He said her parents were in on it, too. They would say everything's okay and then a few days to a week later they'd all have a meeting on something he said or did and talk it out. Friend A told me "I can't even remember what I ate for breakfast, how can I remember what I did days ago?". (*He doesn't have a literal disability that deals with memory loss, although I know long term vs short term memory is different for everyone). I empathize with him, and believe that two to three years ago, friend B would have been capable of doing that. 

The flip side is, friend B told me her side of the story months ago. She said that friend A would steal from her and refused to get a job. (The two of them were living together during that time.) She also believed that friend B liked her, and tried to break her up with their bf at the time. She also told me that she gives everyone three chances, and I believe her because I jacked up our friendship 4 years ago. Once I looked within myself and changed my behavior, I apologized and she forgave me. 

Here's the thing. I don't believe that friend A is lying about what happened back in 2022. When he finished telling me his side of the story, I said "I believe you". However, I've seen friend A grow. She's seeing a therapist now and is getting sober. I have also stayed over at her house since then and she cleaned up regularly and told me she can't stand huge messes. I haven't told either of them that the other has told me about what happened, and in ten days I'll be staying with friend B for the week and going to ComicCon. My biggest fear is that Friend A will somehow find out about it through one of ComicCon's videos or through the vlog I plan on making. Neither of them have spacehey, so they won't find out through this forum and friend A doesn't watch my Youtube videos so maybe I'm worried for nothing, but the guilt and anxiety gnaws at me nonetheless. I can't make myself hate my best friend for what she may have done when she was sixteen, and that I never witnessed. Especially if the behaviors brought up by friend A are most likely being treated now. However I don't want to be fake towards friend A and leave him in the dust. I know he won't want to be friends with me anymore if he finds out.