I would say it is to do with his circulatory system. For some reason his blood has a better composition and is healthier now.He's had some kind of a shock at some stage and it has affected his regard for himself and how he thinks his wife thinks of him. I think he may have developed a slight irregularity in his conduction and this is to do with stress.
What this irregularity is about is that he has been really trying to hang on to ideals with how he think he should have handled things and what he thinks he needs to do to get things sorted out. So yeah, I feel its vocational/financial and his livelihood is under question. He's a really great guy and cares about his responsibilities and significant others.
My suggestion - encourage him to have a health check, just anyway. Take the doctor's advice. Then the big one, self-acceptance despite what his wife is saying, and despite what he thinks he should be doing. He needs to look on this time as a hiatus in which he can give some long overdue constructive nurturing to himself rather than placing himself on a contstantly intense guilt/failure trip. He's always been there for everyone else even as a little boy. He has a backlog of a great dam of emotion and he needs to ease some of this pressure instead of trying to hold it.
So yeah, I'm picturing running, walking/running a dog,blended nutritious drinks, and working seriously at a hobby. Treat this hobby as a mini profession - don't worry about its viability.
And to get over the financial mumbo/jumbo. Sit down and have a very slow cuddly conversation with the wife, sob, tell her how miserable he is about how things have gone and how he's going to try just accepting the situation, (big sigh and letting it all go/out). Do house hubby things - so yeah cooking, washing etc, and I think annoying stuff like(well, it would be annoying to me) - yeah stuff like, massaging shoulders, father confessor for the wife "tell me all about it, ra, ra, ra...", also maybe volunteering to take a neighbour/friend's dog for a walk when he
walks his, getting to know the locals more on shopping jaunts, that kind of thing.
good luck