Tell him to find a headhunter and have them help him find work in his areas of expertise. The benefit of a headhunter is, if they're reputible, they will be discrete as they shop his resume around.
In this economy, I'm with your husband, don't just quit...have a new job lined up before giving notice. Many folks in the brokerage biz easily transfer to insurance (carry many similar licenses), banking, and financial planning. If he hasn't already started expanding his field for searching, he should check these areas as well.
Depending on how well he is networked or what his specialties are, he could go into consulting or on his own as well. A lot more risky in this climate, but it is an option.
Working with a headhunter isn't going to take away the uncertainty, but psychologically it might be helpful for him knowing that he is actively working on making a change.