Jax, Hi, It sounds like this is tormenting you. It would torment me. My Dad was a nightcrawling pedophile. The thing about Thursday's-- is the mother out on thursdays? Drunk Daddy have bowling league? Too weird for me to believe it's "just" a nightmare. I've had night terrors since I was in diapers. (They used to peel me off the window sills....) Is there a crisis line for youth in your area? I think I would call them and ask for advice. Dealing with drunks is for the pros....I'd recommend you cover your butt with anonymity if you choose to report.
Most officials understand these things: they get lots of practice, unfortunately. Given your description of the parents, I'd say the kid needs help one way or the other. Can you find peace without finding out the truth? I'm sending you courage and protection and tons of care. This is the pits of a situation to be in. I don't envy you at all. I hope you get through this soon. I'm concerned for you both. Keep us posted, ok?