Re: Mother is Threatening to Call Police About Minor Daughter's Adult Boyfriend
Your friend needs to stay away.
I'm not going to look up all the relevant WI codes, but if his actions encourage the child from disobeying her parents, run away from home, etc., then there are crimes he can be charged with (custodial interference, contributing to the delinquency of a minor, etc.). If the police respond because he is outside, they will probably tell junior that he should beat it. Whether they could compel his departure depends on where he might be and what he might be doing.
She is trouble for him.
A Nor Cal Police Sergeant
"Make mine a double mocha ...
... and a croissant!"
Walk humbly with your God
-- Courageous, by Casting Crowns