Guys, relax. It's a difficult situation. No need to jump on him for his suing idea, its completely idealistic with his injury.
Unfortunately, it's probably very difficult for him too. My dad had no insurance for a while because he had no money.. and he had to work so he didn't really have a choice to drive or not.
You probably can't force the guy to get insurance, but you can strongly suggest it. Suing would be pointless, and a waste of both of your money..
Good luck.