Watching the show, it becomes absolutely clear that Jodi and Ruby abused those kids. Anyone who has followed the case, even remotely, knows that. Apparently, the only person who doesn’t is Kevin. In the last interview of the show, Kevin says he still loves Ruby, and throughout the documentary, he makes it clear that he would always choose her over his children.
It doesn’t matter how great your memories with someone are—if you find out that they were abusive, and not just abusive but abusive to children, your children, and to such an extreme degree, your perspective changes. If it doesn’t, it’s because you knew, or at the very least, you don’t care.
I sincerely hope none of those kids ever have contact with Kevin again and that they finally receive the love and support their parents were supposed to provide.
Oh, and by the way: Ruby and Jodi were clearly involved with each other. Nothing like faking demonic possession to get into your girlfriend’s house and kick her husband out.