Well, it's up to the lawyers, now! Very likely both Germanwings and Lufthansa will be in serious financial trouble. Lufthansa admits it knew Lubitz was unstable; Germanwings spokesperson disclaimed any prior knowlege at all!
For an airline to escape liability it must prove it was entirely free from blame.
1. Still all up to investigations and filing the facts. For the next months.
2. Germanwings belongs entirely to LH.
3. Lufthansa flight school knew about a phase of depression during his time becoming a professional pilot. Apparently the actual flight management did not know he was still "unstable" these days.
4. And he wasn't unstable according his colleagues but rather a good pilot.
5. Germany is not the UK, not such a blame society there. Innocent until proven guilty as far as I am aware.
People who do up simplified and ignorant comments like this should better watch out the next Lubitz could be from one of their friends or family.