Yes, RV, stories like this absolutely confound me. I can't figure out where in their heads people make sense out of pulling crap like this on their children.
As for the immigration paperwork, if she lives in a smaller city she may even be able to get a couple officers from the local precinct to accompany her (a police escort is the right terminology, I think) to the in-laws home to ask for the paperwork, and that way they may be less inclined to refuse. Might be harder to swing in a big city where they have other 'priorities', but they are supposed to help with things like this, and it will also help provide official documentation if they refuse.