Listen, I know it isn't perhaps the RIGHT thing to do, but if my DD went missing just hours after she was in the "care" of my ex, I'd be all over the blame game, freaking out, demanding to know what the he77 happened and asserting that this wouldn't have happened on MY watch.
And I have a pretty good parenting relationship with my ex. But when it comes to my DD, the crazy lady who lives in my head would be busting a move.
Dylan went missing from Dad's house. Of COURSE Mom is gonna blame Dad. Even without the past anger issues, etc.
Doesn't mean MH isn't responsible, just means that even if he weren't, ER would likely see him as the person to blame.