I went through a period of severe depression following some life-changing events. These changes caused me to suddenly become isolated from my family so my wife was really all I had. I lost my job and struggled to find another one in the industry which only made things worse and made it so that we didn't really have money for therapy. It was a rough few years, but we made it through.
The best thing you can do for him right now is to be there for him and remain his ally. Try to make him smile when you can and give him hope for a brighter future. If you want to do something more pro-active then you could try to keep his space clean or cook healthy meals for him as these things will help with his mental hygiene, but it's mostly up to him to make the necessary effort to get better.
Make sure you take care of yourself, too. Practice good mental hygiene so that you can stay positive and motivated to make it through this. You got this.
Well America used to be just a handful of colonies along the eastern seaboard, but then there was the whole manifest destiny thing. Going west meant heading out to the new frontier. Midwesterners are people who gave up midway.