I can only tell you what BW's parents knew, not the extended family (especially WWH and MWK). They knew about DH being investigated because he was not staying at home due to the pending investigation. However, I don't know that they believed the allegations [don't shoot the messenger!], maybe because they didn't know much about the facts of the case or what exactly he was accused of. We all know of instances where people are accused of things they are not guilty of, so my guess is they wanted to believe in his innocence. I'm not saying that was right, I'm just saying I believe that's what was going on.
BW's parents & step-parents did NOT KNOW about RSW & DK being investigated. They were only informed after the arrests were made and they were devastated. They're not actors--they were devastated. I knew about DH's pending investigation prior to the MWM reporting it, but I hadn't heard a whisper about anyone else being involved in anything. There may be those who doubt, but of this, I have no doubt.
I wish I could say you are mistaken about BW's drug use, but she was described as heavy into meth. When she had custody of PH, the DHR got involved and that is how AH ended up with custody of PH. But you are right about her having a hard life.
My sincere hope is she had little to no knowledge of the sexual abuse going on. Because of her drug use and the importance it had in her life, I believe many of her actions were motivated by it. I believe she went to see DH relating to her drug use. There was some history there and that's one of the reasons she hung out with him.
I am not attempting to malign anyone, simply provided some personal knowledge of her lifestyle, background, and typical behavior in order to shed light on what may have factored into her disappearance. For those who may not have had the opportunity to read the 45 pages here and those in the previous thread, I am a verified insider in this case and have been given permission to present information without the need for sources based on my personal relationship with BW and her family.