Sale of Aer Lingus

What happens if the United Kingdom leaves the EU? IAG will no longer be within the EU. Where does that place Aer Lingus?

It would seem that selling the company for €1.3 billion is a bargain deal for IAG. Aer Lingus has 50 aircraft, an extensive property portfolio, cash reserves of €1bn. Then the famous Heathrow slots. Alone, the Aer Lingus brand is worth a small fortune.

There's seems something terribly wrong about this deal.