He's beloved by a certain right-leaning or libertarian bent portion of the tech world, and everyone else except for maybe Google's lawyers have forgotten about him. So it seems like he is in a better place now than simply being a midlevel employee in MegaCorp
I really doubt it is with his own money. Google pays pretty well, but he was only employed for a couple of years outside of school, so I doubt he has millions just sitting around. Almost certainly this case is taken on a contingency basis or they are using crowdsourced funds.