Well, he won't, not even with the slightly loony Graveney in charge. You'd have to be a Monster Raving Loony, perhaps even head of the Monster raving loony Party, to even suggest it.
He could, but I think the rules are ludicrous to even allow it, tho I know it's happened before (was Kepler Wessels the last to play for more than one country at test level?).
To hell with qualification periods and qualification by marriage or great-grandparentage or whatever, you should only qualify for one country, and that should be the country where you spent most of your years up to the age 18, the country that shaped you as a person and a cricketer, before you even get the notion to pick and choose your allegiences based on which side you think you might get into.
I realise that would have meant England would have had no Lamb, Hick, RA.Smith, Pietersen, etc. But I'm not sure that's a bad thing. At least then we could have been rightly proud of our victories.