The people who need to be sued are EASA. It was their system that made the rules, their system performed the oversight and their system that let them down. What happened could have been anticipated because this sort of thing has already happened. Over the years I have flown with various people who have not been mentally fit for flight. Some because of their immature and childish way of dealing with things that don't give as they anticipated and others because of their mental state (medically that is). The difference between the two is that those who were medically I'll have all returned better people. More importantly, they were fixed, so to speak.
So if EASA are taken to court and if (or more likely, when) they lose, the money should come out of their pension fund. They don't deserve the air they breathe.
PM