My husband (64) has debilitating Diabetic Neuropathy, depression and severe pain. Any ideas?

What kind of pain meds have his doctors tried? Have they tried every single pain pill that's out there? If not, then they need to start eliminating the ones that don't work and find one that does.
Remember that any doctor is the hireling, they work for you so keep looking till you find one that's worth your hard earned money.