I'm going to tell my dad that his girlfriend could be my sister and make fun of her
I hope you are joking! Why would you say something like that?
He just has to know, she is so creepy. It's obvious that she wears gowns for my dad not herself
I think that you should not meddle in their relationship. Besides it is not nice to make fun of people.
What are you talking about I'm only kidding.
Kidding or not, it is rude to make fun of people. You should be nicer to the people your dad brings home. You don't know anything about them unless you try and get to know them.