He has a brain disease that makes him believe that nothing can ever get better. If he had a leg disease that made him unable to walk then would you blame him if he couldn't meet you halfway across the room?

For most people, depression is episodic. There will come a point when he starts to feel a little better, and will be more amenable to taking steps to feel even better. There are effective treatments that can help him get better and stay better. Having social support from loved ones is the strongest predictor of both getting better and staying better.

But there is not a cure, and he will never be "fixed." Some times will be better than right now, and sometimes will be worse.

You don't have to stay married to him. You can do whatever you want. This doesn't seem like "he should work more hours" problem though.