There is little doubt that they have been communicating between themselves. I heard from a rather reliable source that airlines are asking the EU for some relief from EC261.
It's not to easy for the EU Parliament to change a law and apply it retroactively. Basically, the parliament would need to scrap or rewrite EC261/2004 article 8, which (today) requires the airline to issue a full refund.
If the EU parliament pushes through a retroactive change, you can bet that pax and claim agencies will challenge that at the European Court of Justice.