Now I'm no medical fag or anything so please take this with a couple grains of salt, but I've been reading up on Cushing's syndrome since a family friend was diagnosed and... I've got to say, it sounds a lot like Chris.
Basically, the cortisol imbalance can lead to a "moon face," weight gain around the belly, skinny arms and legs, and even gynomastia (basically breast growth) in men. Sound like anyone we know? Its also linked with depression and some other issues, but the physical traits sound frighteningly like OPL.
Has anyone ever brought this up before? Honestly I'd be surprised if he had untreated Cushing's because I don't think he would make it this long, but maybe it's something he's developed over the past few years and nobody noticed because he was already pretty weird looking. Who knows. Just food for thought.