Pissed off at my dad

My dad has been staying with me for a while because he's getting repairs done on his home after the hurricane. He's been drinking a lot lately and being flat out annoying. I babysat my friend's kids. My husband's little brother was visiting and had a friend over. First thing my dad did that got me in trouble with my friend is he MOONED her kids as a joke. These kids are 5 and 7 and he's lucky he didn't press charges on him for exposing his ass to them! She is really upset with me which I understand. Then my BIL calls my husband after him and his friend left. Apparently my husband's brother's friend was being annoying and my dad told this 18 year old that if he does that again he's going to fuck him in the ass without lube. I have never been so humiliated in my life and idek how how handle this with my dad.

Edit: My dad is not a predator. He's just a dumb alcoholic who does stupid things when drunk. He mooned the kids to be funny even though it wasn't. While it was 100% inappropriate he wasn't swinging his penis. He showed his butt not to be a predator but to be "funny"

Edit2: My dad was drunk. Still wrong but he never would have done this sober. I'm not going to throw around the word predator. My dad doesn't want to be with children and he doesn't want to rape 18 year old boys. My dad is actually pretty homophobic. He was drunk and did a lot of inappropriate things. That's it