While North Carolina has some of the most liberal statutes in regards XXXXX XXXXX offenses, the activities you have described still appear to be criminal in nature. Pursuant to North Carolina law, it is criminal for a person to engage in sexual activity with a minor residing in their home. As such, the 39 year old woman could be arrested and prosecuted for a sex offense.
If she were arrested, especially for an offense listing your nephew as the victim, your nephew would surely be prohibited from residing in the home. As such, the logical place for him to reside would be with you.
Having said all of that, I have to wonder if this may be an exercise in futility. As his 18th birthday is XXXXX a month away, he is one month away from being a legal adult and being able to reside wherever he desires. Purely speculative, of course, but it is foreseeable that you would call the police and have her arrested only to alienate your nephew and have him leave your home in a month. This is a personal issue, not a legal one, and I will certainly leave that to your sound discretion.
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