Is my fiancé crossing a boundary by privately checking on my niece?

My niece just moved in with us. I recently discovered that she and my fiancé check in on each other through text. He asked her if she was okay, she said no, and he replied, "Want me to come, or do you not want to talk about it?" I feel that crosses a boundary, and I didn't know about it. I was using his laptop when the message came in. What do you think?

Is my fiancé crossing a boundary by privately checking on my niece?
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