I think this is an unfair assessment, especially given the turn of events today. This family will have enough pain and guilt to deal with without us heaping it on them as well.
It is also unfair to judge how YOU might have done it differently because you weren't there. And to be fair, we don't know the entire living situation. We haven't seen many pictures and the ones we have seen are in question. Do we know for sure that the inside of that trailer wasn't clean? Do we know that the family was even aware or had been there? Did they maybe just take Matthew's word for it, not knowing what he was capable of?
By the way, do you have adult children? What exactly do you propose that they should have done? Because sometimes there is only so much you can do. As adults, they will still make their own choices and sometimes they are bad ones. And yes, sometimes those bad choices will have far-reaching consequences for others. But there is still only so much you can do.
Given the circumstances today, I would ask that we please with hold our judgment of this family for now. They need prayers and Ember needs to be found. Judgment and accusations can happen later.