I'm Lucy, and I'd be happy to answer your questions today. I'm sorry to hear that this happened.
I'm sorry to say, unless the father signed something where he legally terminated his rights and gave you guardianship, he still legally has a right to insist that his child return home. If he calls police and tell them that his child is a runaway, hiding in your home, police can and will pick him up and return him to his father unless you have a court order that says he gets to live with you (or a written agreement from the father). Neither your nor the child will be charged with a crime if the child is there voluntarily, because he's over the age of sixteen. See G. L. c. 265, Section 26.
If you have ANY reason at all to believe that the child is in danger, call Child Protective Services and ask them to intervene. You also have the ability to go to the courthouse and seek involuntary termination of the parent's rights, along with a court order granting you guardianship until the child turns 18. It may not be not enough that the father is hostile, unless it rises to the level of emotional abuse, and emotional abuse can be tough to prove. That's a complicated process, so if you want to go that route, it's best to hire a local attorney.
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