When you remember that Joe told Abby to hold her little brother's hand, after you learn what Emily had done
Poor Henry. Upon realizing that his wife has possibly killed his son, and in front of his daughter too, after what appears to be a long and protracted battle with a mental hospital and custody issues.
Emily, when she comes round from her psychotic episode and realizes what she's done to her own child.
Abby. What did she see before Joe even called to check on her? How long was she standing there with her brother's blood on her? And how is she going to handle this trauma as she grows up?
All we know about Oliver's fate is that he survived. Given all the comments about the amount of blood found at the scene and the fact that Emily tried to "get the snakes out" of him, he likely suffered grievous injuries. Who knows what kind of scarring and long-term damage he'll endure.
Henry, again. Even though it's never stated he's a good father or a decent citizen, he's just trying to help his wife and it ends up looking like he's the one who hurt Oliver and abducted his wife in a fit of anger.
By the end of the movie, Henry is suffering from a head injury from where Emily hit him with a brick, he's desperately trying to get home to Abby, but the police who are with Abby have been told that Henry killed Oliver and he is armed with a knife. By the end of the movie, none of this is cleared up by Joe. Henry seems likely to die.
