I wish my friend would leave her crazy boyfriend
Why do you want your friend to leave her boyfriend?
They are in an open relationship
If your friend agrees to be in an open relationship, then it is none of your business. How your friend decides to live is her own business and it is between her and her boyfriend.
I know but my friend is naive and she doesn't know how to hold a relationship. She is too young for him and I have to step in to set her straight about all this.
Your friend's dating relationships are her business alone. You stepping in to help is really just interference. Stick to your own relationships.