If this suit goes forward it will be interesting to see what sort of questions are raised and then answered.
From what I had as training to renew my FAA CFI, from that module on security, it was pretty clear that simply having someone show up with a Student Pilot license/Third Class medical and money was not enough to pass him along as safe; we seem to be expected, as CFIs, and as schools too, to make some sort of independent threat assessment.
This module was aimed at terrorism, such things as seeming to be under the control of a third party, wanting to pay with cash, not seeming to have a sound reason for doing some particular sort of training, asking odd questions about sensitive locations ... but it's easy to stretch that a bit to think that we are supposed to be "heads up" about other sorts of threats too, such as someone possibly hiding mental problems.
"How far to take that" that might be one of the questions raised and answered.
Another one might be to ask if Lubitz was mentally ill at the time he received his training, along with asking if the FAA probably would have issued him a First Class as they did issue him a Third Class medical, given his history of depression.