Should I stay or should I go?

My boyfriend of two years is a great guy and my best friend. His luck over the past few months has been awful. The economy has been awful and due to city budget reasons he was given a pink slip. He has had a history of depression which he had somewhat under control. Now that he is unemployed, living with his parents to help take care of them (they are elderly), and currently on Cobra for health care, his depression has gotten out of control. He has told me he knows he is depressed but feels stuck, wants to get help but can't afford it. He says he feels lost without a job and ashamed for people to see him.
We have had lots of long talks about this. He gets frustrated and can't make decisions. A few weeks ago he admitted that he is unsure about so many things that he doesn't know how he feels about me. He wants me in his life and doesn't want to lose me. But on the same hand he feels he is a failure and doesn't want the responsibility of being with someone so that he has failed them to.
He knows it is unfair to string me along, but doesn't want to see me go. But doesn't want to make me unhappy. He wants to stay together while he works through this depression.
I care a lot about him , and I know his sense of worth has been damaged by this sudden layoff and inability to find a new job . I feel torn with what to do. Should I stay and allow him to work through this in his own way? (Which I am ok with) and if so .. How long do I give him to work through this? Or should I break it off as friends and let him work on his problems on his own.