I have a relative by marriage who worked with him on a film years ago (yes, before Callista Flockhart), and said he was drunk constantly on the set. Then I saw him on "The Daily Show" about 18 months ago: he could barely get a sentence out. Maybe there's not much else to do on his ranch in Montana (or wherever it is).
I should say that, despite this, I'm quite a fan of his. Bladerunner is one of my favorite films; I also loved the Indiana Jones movies, and am looking forward to the next one.
Chad