回复：帮朋友的朋友问一下 － 劳资纠纷 － “打击报复”

If there is a lawsuit, it must be filed in China. It can be filed in US but it is more than likely a US court will dismiss such a suit based on forum non conveniens.

If this was sued in the US, then yes, whistleblower protection is one of the key grounds for an employment lawsuit. He can sue the company or the firing manager individually. In terms of Chinese law, this guy has to consult local attorneys there.