Earlier quoted context omitted.
Seeing as how the actual mechanics of the leak were orchestrated by an attorney, and the documents were sent to an enforcement division of the Federal Government, it would be a pretty fair guess that they have considered it and are on solid legal ground.
Are they operating pro bono? If not, they may simply take the case because it will generate a lot of work for them, and it’s likely that such a public case could attract plenty of donations to fund the cause. Having argued a high profile case against Facebook is a huge reputation boost for a lawyer.
They are a public interest non-profit: https://whistlebloweraid.org/vision/