> Even if she did, would she have been able to even stay while the lawsuit plays out over months to years? Unlikely.

It is not necessary for a plaintiff to be a U.S. resident for a lawsuit to proceed in a U.S court.

I'm not an expert on immigration law, but if a foreign resident needs to appear as a witness at trial in a U.S. court, then they can usually enter on a tourist visa or some other visa.