Let's see...
He's financially ruined.
Bankrupt.
Lost his home.
Feels like a failure.
Is living with his gf's mom.
Is unable to feel like he properly provides for himself, let alone you.
Yeah, I wouldn't be able to get it up either. Thanks for being understanding...
Don't accuse him of anything, don't make any passive-aggressive comments about him not wanting sex. Basically, you have to treat him like life is normal, so that he can feel somewhat normal. As far as I can tell, this economy has a lot of people very down, and he's now one of them. Welcome to the world of capitalism, where you **** not only those under you, but other countries as well in the process now.
Global economy. Yay!
Recommend he get some therapy, get out of the house, do anything. Build a plan to recovery from bankruptcy. But, more than anything you need to build a routine that is comfortable for the two of you again. It isn't the end of the world, and frankly. God isn't going to help him, because even if God existed, he doesn't work that way.
"Well, then," the Cat went on, "you see a dog growls when it's angry, and wags its tail when it's pleased. Now I growl when I'm pleased, and wag my tail when I'm angry. Therefore I'm mad."