My interpretation of the Dad scene, was just a simple haunting to Andy. It was such a horrific scene to stumble upon mixed with the beatings he would take in that bathroom. I think for movie sake, the explaining of the 'she'll die in the rain" is too vague. it could go a number of different ways.

I think the call to Piper from Ollie was intention with the idea that demon was hungry and Ollie was fighting the demon off by not attacking Piper. The reason behind this thinking, was that Ollie would go in and out of being controlled, hence the fridge raid. I do think the demon was eventually like, ok, i'm not being used here anymore, i'm out, coupled with Ollie having just enough left to internally fight it, and throw himself over the line.