Why exactly can he not really take any pain meds? Can he take any muscle relaxers? The muscle relaxers really might help with the muscle stiffness. As for the nervepain there are several other medications that he could try.
Amitryptilene, Nortiptylene (both tricyclic antidepressants that help nervepain)
Lyrica - a fairly new medication similar to Neurontin (gabapentin) that helped a lot of people with nervepain including me
Ultram - a synthetic opiod, very weak narcotic medication (although many doctors do not consider it to be a narcotic) - very good fornervepain
Cymbalta - an antidepressant that is also very good fornervepain.
I think that he might definitely do better on one of these other anti-depressants such as the Cymbalta because they are clinically show to help nervepain.
He may need to resort to narcotic medications if he can not tolerate the pain. They may be just what he needs in order to be able to function better. However, the above medications should definitely be tried first. Hope this helps and if you have any other questions feel free to ask.