I have zero experience with this and I'm sorry you are in this situation.
If I were you I would do everything in my power to get a new living situation. Subsidized housing, whatever you can do. Why is your Husband not working right now?
As for the elder abuse accusation, is there some kind of free legal aid in your area at all? I would start researching. You can certainly out your Father's meth addiction but at the same time you will be throwing yourself under the bus bringing a child in to a house where there is an active addict.
Just tell the truth, the story as you have told here, he hit you, you put the book in his face, what more can you do? They will decide what to do from there but a chat with a lawyer would help to put your mind at rest.
You need to get out of there. That should be your number one priority right now. The rest of it will solve itself by removing yourself from that incredibly unhealthy situation. Have you researched what assistance might be available to you or even to you and your child after it is born? If not I would do that right away.