I guess since many people think your H needs meds, you have have to ask yourself how long you are going to give him for his plan (IC alone? IC and exercise?) to work. And if it doesn't work, how long you are going to give him to realize he may need to try meds?
The depression issue is complex and very tied into self-care. If any of us were to get depressed and let it run its course for however long it takes every time it got "triggered" or chemicals changed or whatever happened, it could take years and cause a lot of pain and grumpiness along the way.
From the post above, you sound almost lucky to be separated from H right now. The problem is getting bounced on his family. You might want to figure out a way to stay dim and restrict your contact with H to once or twice a week to get off his rollercoaster. Have him agree to it ahead of time so he doesn't keep texting and emailing you with every mood he has.
