What would you do if you were the parents of the kids in this situation?

The parent of a 20 year old guy is moving in to their partner's place. Their partner has a daughter that's 22 years old.

Before they even move in fully, the son sexually harasses the daughter of their partner by asking if they can fuck them. They do not take no for an answer and press the question continuously. Every time they are in the daughter's presence, they are extremely inappropriate.

If you were the parent of either the son or the daughter, what would be your course of action in this scenario? Describe what you would do in each parent's scenario.
What would you do if you were the parents of the kids in this situation?
Updates
1 mo
I forgot to mention that the daughter has brought this to both parents attention.
What would you do if you were the parents of the kids in this situation?
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