Elliot!
So, Elliot just had half his face burned off and the demon is dragging him into a boiling pit...
... and the dad just stands there yelling Elliot, like Elliot can just stop it.
Good point but still:
Until that point, three deaths had occurred (two directly related to the house/being in or near the house), daughter dead, wife berserk, and on top of that, psychics storming the house and seeing an actual satanic figure that could rip you to shreds, yeah, I think he did pretty damn good staying away and getting the hell out of there. I'm surprised he didn't get attacked himself, being so close. I would have been freaking out and I'm sure he was close to wetting himself.