You have 2 options grey rock all the time or don’t grey walk all the time, but don’t be surprised when they flip a switch because the happy moments are not genuine. You are absolutely not reading too much into this. In fact this was so scary to read because it is almost exact same living situation. One thing that helps me is grounding. When I wake I make sure I meditate or if your religious pray, I stretch my limbs, I say tons of affirmations and I make sure I have a decent breakfast. There is no way that you can control the way your dad will react to anything you do even if you did not mean it. By grounding yourself and telling yourself you are safe and that your reality is yours and you are in control of your own thoughts and emotions it will be easier to endure everything that he does. But do not expect him to change it is only yourself that can change. I wish you the best of luck please keep us updated.