In my opinion, it would not be a good idea for any government to try to address unemployment using Forex for the following reasons:
1.) Forex trading requires a level of knowledge, experience, and (frankly) intelligence not always found in the wider public. Some would lose a lot of money. Many would insist it not be so hard. Many would blame the government for there losses.
2.) There are certain technology requirements (high bandwidth internet, computers, etc.). As such, any attempt to broadly introduce Forex trading to the general public would benefit those with the tech already (i.e., the richer part of a society).
3.) Forex trading exploits market inefficiencies too minor to be correct by other means. This means that, the more people attempting to profit from Forex, the fewer opportunities exist and lesser the profits for all. It is not really clear just how many more traders could continue to profit from Forex, but I do not think millions of more traders could possibly continue to profit at today's levels.
Any attempt by a government to address unemployment would need to be fairly applied and accessible to all. It would need to take into account the poorest, most vulnerable, and least educated.