Hi hvert, well it sounds like you've really tried to help him over the time. And real kudos to you for that!!! I'm sure there would be friends out there who would have walked away before now in that situation.
As for his partner, well they say love can be blind don't they??!! But maybe living with him day-in-day out she hasn't noticed the deteriation as much if it was a gradual thing or is finding it hard to completely accept or admit to herself, maybe she's hoping she can be enough to help him get by, or maybe she's worried he'll be hospitalized if she really tells someone how it is (and she might have lots of concerns over that even if it might be the right thing).
But if it's you he's really opening up to in e-mails could you contact his partner/"wife" (you are absolutely sure they got married aren't you- not something he's just said??!!) express your concerns, send her the e-mails (might give her a "wake-up-call") and hope she can help him get some kind of support with what he's going through. If you can do that there's a chance he may find out and he may well not thank you for doing it. But if there are no other options/he won't listen to you, and he might be at risk, then it's his best interests you have at heart isn't it. Could even drop a call to- is it Human Services you have over there??? if you think he might be at risk?????
Or if there are any charities/support groups/programmes in his area maybe he might be more willing to try them if you drop him some details. They may not seem as "threatening" (or any of the other things he might be thinking) as seeing a pdoc.
Still there is only so much you can do, and again real kudos to you for trying, for caring!!!

Alison