this falls under the category of "house squatters" get a lawyer, and they will issue to get the legal right for them to get out of the place.
It is probably even more complicated than that, if she is living with the son in a separate building on the same land.
Depending on how much you care about getting the son in trouble, waiting until there are drugs or other illegal items in the trailer and then calling the police is one option.
yea, that's my fear. course he's run out his welcome too, at this stage. just one problem at a time seems to be the method here.
were it left in my hands, she'd be gone in a few hours. him too. scare the fucking shit out of them. i'd like to think it'd be easy. sigh.