Life insurance companies are smart about risk. They know we are ALL going to die sometime — but pricing the risk typically depends on age and health. Some health conditions are just too risky for them to underwrite at all. I suspect your husband falls in that category. And if a company were to write this policy, it would be so expensive. You may be better off saving those premiums and building up a self-insurance fund. Just set the money aside for the eventuality that he will predecease you.
Of course, you could try another insurance broker, and some do specialize in high-risk situations. But then you will have to decide whether you really, really want to pay all that money on a bet against your husband’s longevity!