If she was eighteen at the time the child was conceived, it's none of their business.
If the child was/is a term baby and was/is born less than nine months after her eighteenth birthday, you might might have a misdemeanor level problem.
Do not post any clarifying information on this public website. If you have a concern, schedule a confidential consult with a local lawyer.
This answer is provided for general information only. No legal advice can be given without a consult as to the specifics of the case.