Yes, he knows. Luckily my son wasn't drinking, but they were playing a dice game where you call shots and then whoever rolls a 21 drinks it. He was rolling the dice for a girl who didn't understand the game. He was 10 at the time.
You would THINK the so-called adult baby sitter (she's 34) would tell her friend that this is an adult-only activity and that my son should go back to playing with the other kids, but no.
When I reported my ex for hitting my daughter and leaving marks, Human Services told him and me that it was acceptable discipline but that he should consider anger management classes.

I even called him after she called me, crying so hard she could barely talk. He laughed and said she deserved it. She was having a temper tantrum and slamming her door, so he hit her with a belt.