M.L.
My husband isn't a Pollyanna - no, ma'am! - but I am.
Have you ever read the Pollyanna books? They're very old, and they sound sugary to modern ears, but they're worth reading and you might be able to find them at the library. They're children's stories about an orphaned girl whose papa, before he died, taught her a game of finding the good in anything that happened. He taught it to her because their life was very difficult and he didn't want her to grow up bitter. It helped them face the hard times, and it stood the little girl in good stead when she had to go live with a bitter, angry relative who didn't love her at all.
Let him be as positive and upbeat as he wants. I have no doubt that he understands the seriousness of his situation (especially since he lost his assistant!). This is one of the ways he's handling it. Think of the alternative: do you really want a grouchy, angry, bitter husband around the house?
If he isn't sure what to do, then the problem is his future, not his attitude. You can say, "Well, I'm amazed that you can keep on smiling. But I wish we could sit down over dinner some time and think about some plans for the future. If you'll at least think about the alternatives, I'll do whatever you need to help with them, and I'll even smile for you if you want. Or I'll smile *at* you if that's better!"