It would be irresponsible not to speculate. Via Andrew Stephen in the UK's New Statesman:

Rumours persist here[In DC] (and I have heard them repeated at a very senior level in the UK, too) that Bush has actually resumed drinking; I throw this into the mix not to sensationalise, but because I have now heard the rumour repeated at a sufficiently high level that I believe we must face the possibility that it might be true.

I'm not sure whether Bush as a dry drunk, or Bush as a wet drunk, is more worrisome. Maybe Henry Kissinger could call on his experience with Nixon, and share his wisdom?

Bush was huddled inside the White House eating beef and ice cream on election night with Rove, my friend Josh Bolten, and four other trusted aides who will stick with him to the end. He was not drinking on this occasion, I'm assured - but, more than ever, my depiction of an unstable man living out his final days in office inside his bunker seem no longer to be fanciful. Hemmed in by Democratic foes wherever he looks, determined to be remembered in history as an unwaveringly strong leader, and increasingly detached from reality: now that suddenly becomes a very frightening vision indeed.

Beef and ice cream...

NOTE Link thanks to the lovely, the talented Avedon.

UPDATE And when we say, "again," we mean "again".