Debt is very stressful. I can imagine how helpless it would feel to be in debt "beyond what you can imagine" and not be able to make progress on it because your spouse isn't on board. The thing about debt is that, for the most part, we all know what it takes to get rid of it. We know our income and expenses, and what we need to cut to make it work. We know to pay off expenses with the highest interest rates first. And I think we typically know when it's best to sell something, or keep it, in terms of its resale value versus usefulness to us. (I say because cars seem to be one of your assets, and of course having transportation can be less costly than the alternatives - so not necessarily a bad decision to buy or keep a car that could otherwise sell and pay off debts.)
In the end, I think it's just about resolve. You (both) have to come to that point that you sit down and make that budget, and then follow through. And if it doesn't add up, you have to be willing to put those "investments" on that table until it does. And it's possible that it won't...
That could be a really stressful prospect for him. Maybe your husband is afraid that his assets just won't add up to the point that a viable budget is possible? So he's afraid to even approach the math, hoping instead that some investment will turn up worthwhile and he can fix it then...
I know that's not a solution. I'm just trying to brainstorm what his though process might be.