I've never heard of this before you mentioned this treatment, and I thought I had read everything. I have a tens unit that seems to be based on the same theory, of a small electronic pulse to help relieve the stress on the muscles. I just couldn't imagine the pain it would cause me to put this on an area with RSD. I am able to use it on unaffected areas, that get muscle pain from overcompensation, etc. As my RSD is spreading I am not able to use it much at all.
The articles I've been reading on the machine say it's very much based on acupuncture and reflexology points. These are very exact points on our body that take years of training for people to learn. I think it would be a little scary just hoping you get the right points and then allowing an electrical current to flow.
Also I had a spinal cord stimulator implanted about six months ago. I can not use it at all now. The electrical stimulation went to the wrong nerves and caused my RSD to spread to those areas quickly and intensely. And this was under the supervision of a neurosurgeon and a pain management doctor.
Is it possible to have your local pain doctor contact Dr. Rhodes about working out a protocol through him? I worry for your husband if electric currents are being sent through the wrong acupressure points. Have you tried contacting any physical therapists in your area that may have experience with this machine in the past? Also have you tried finding a used copy of the book on e-bay or a similar used site?
I wish you all the luck. You've peaked my interest as I've never heard of this before. I will write back if I find any information that may help you.

Take care.