I really wish there was a place in me that could believe or at least feel he was some what innocent, but there isn't. I've gone through every scenario in my head and at the end of the day, he is always involved in some aspect.
I don't believe EB is fully capable of doing all that was done by herself. I also don't believe someone is that detached from their family/home that they didn't notice a crime scene taking place.
According to AB, both him and EB "slept in" the day Z went "missing". So, if he saw her at 2AM that morning and EB was in bed next to him the entire time (after the fire of course), how did she go about driving around the County disposing of body parts?
It's just such a bizarre story on his end, JMHO.