You only posed the question to one specific person, but I felt compelled to answer anyway since it's a strange situation to be in and therefore, interesting to discuss.
At 17, I don't think I had yet fully grasped the fact that my parents were normal, real people with the same emotions, feelings, troubles etc as any other normal adults. My parents were superhumans/parents. (Sort of akin to how it's odd at that age to grasp that your teachers are just normal people- if you see them outside of school at the grocery store or [gasp] a bar)
That, coupled with the fact that no one ever wants to believe someone they love is capable of evil, would make it very, very hard for teenager me to grasp even the possibility that one of my parents could harm the other, no matter how much evidence there may be to support it.
We see this over and over in cases here where it's only adults involved. Denial due not to lack of evidence or not knowing where the case is likely heading based on previous cases, but denial due to it's simply very hard to accept the truth when the truth is going to either destroy you, destroy your idea of someone else, obliterate your family, or all of the above.
Bill's story has been that he thinks Cheryl ran out on them and has failed to elaborate more on that because he "doesn't want to say hurtful things that will be hard to hear" (paraphrasing) so it's not a huge stretch to think that the daughter could possibly explain away the man in Black with the white gloves as being someone else besides her father.
There reportedly wasn't a history of domestic abuse, either. It's likely hard to envision your father, someone you love, as graduating straight to murder without any domestic abuse previously. It isn't often that husband's go from 0 to murder.
There are 3 options for what happened to Cheryl:
1. Bill killed Cheryl
2. A stranger or someone else known to her killed Cheryl.
3. Cheryl ran off (either alone or with someone) thus deserting her family.
None of these options would be easy for a daughter to accept.
People even on this thread (to include you, Tim
![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
) Have gone back and forth on our thoughts of what may have possibly happened to Cheryl. If we, as mere bystanders can't be 101% certain, how could a teenager be expected to know and accept what happened without being 101% certain?
Cheryl's mom (and other family members) do need support. But it's not up to a minor child, suffering her own loss and huge life changes, to provide that for the adult relatives around her. That doesn't make her a fragile "piece of fine China" and doesn't mean she enjoys having her mother gone so that she "can happily play house with her dad and his mistress, whom he immediately had move into her mother's home."
Her only worry at this point should be high school and perhaps college, or whatever her plans after high school are. She has enough on her plate to deal with currently, imo, without uninvolved strangers placing unnecessary pressure and guilt upon her. She's a high schooler. A minor child who lost her mother under terrible circumstances. She's probably deeply depressed and just in survival mode at this point. Lay off.