I personally gravitate towards odd ducks like Alan, so I might have struck up a weekly email correspondence, if only to gain a sense for what makes him tick. I would have challenged him on a few points of his Shakespearean criticism and humored him so he didn't have to feel so lonely.

After some back and forth on that I would have started asking him more about his life. I'd gently guide him towards courses of action that would naturally guide towards better health and success, like exercising, talking to real people, anything but whatever it is he does for 100+ hours every week.

I'd keep it to 30 minutes a week to put a cap on it so he doesn't start running my life. But you'd be amazed at what you can do for someone just with that small amount of time.