Hello and Welcome to the Pain Management Forum.
My heart goes out to you and your husband. I wish I had an answer for you, I am sorry I don't.
It sounds like you have consulted some of the best Clinics available. I can tell you I would not give up. His condition sounds extreme. I assume you are from Canada. I know they have strict guidelines. Have you considered a consult with the Mayo Clinics in the USA? They are awesome.
We also have other Forums in MedHelp where I would encourage you to copy and paste your thread. Here's the links:
The above Forums may not have an exact answer for you... but they may lead you to someone that can help.
Keep searching. I imagine this is extremely frustrating to say the least. We can fight better when we know what we are dealing with or facing... but when we have no real answers it must be very difficult. You have my empathy.
Please keep in touch. I'll look forward to your updates. I pray you'll find some answers.
My Best to You and Your Husband,