I totally agree with Mark and while I think Adam is in this up to his eyeballs (because when you let some beat your child you are responsible for the damage that follows, and I think he is actively involved in the cover up)...
I think these two had time to concoct this ridiculous charade they put together and she will see the writing on the wall before he does and it all comes down to he said she said on how the death occurred.
If he does not get in front of it, and it may be too late, she is going to bury him at every opportunity. She was beaten, she was afraid, he made her write the note, he made her help with the clean up, yes she did things wrong, she was drug addict, she made mistakes in disciplining Z, the things people have said about her are true, but he killed Z, he threatened her, her forced her to comply.
How do you prove otherwise? The evidence of what happened is diminishing every single day.
Adam is in deep trouble in my opinion.
Even if she can't cut a deal that puts the majority of responsibility on him she is not going down alone. He had a brief window to help solve this case in my opinion and he squandered in.
imo of course