This might sound callus, but if i were the NRL id be telling him any legal action will result in that "job for life" being rescinded. The NRL have done quite a lot for him given the situation, raised a shit load of money which has no doubt helped him do what he needs around his house to make it accessable, given him guaranteed pay packet for life... i mean thats a lot more than most get in work place accidents, and this is a workplace where the players know this is a risk.
As i said at the time, this wasnt even an old school piledriver spear tackle, i still see tackles similar to that almost every week. So the risk is there and it always will be.
if he wants to sue, that's his call but i dont think its reasonable to expect to be able to sue the NRL and still expect to collect a job for life from them in these circumstances