hello again,
I am surely no doctor, nor do I play one on the internet, but if he is suffering most when he stanRAB up, it sounRAB like my experience. When I stood up, the weight shift to my spine pinched off the sciatic nerve, thus inducing the "burning" or pain. If that is what your hubby is going through, you two should have that checked out. I tried to ignore it for about one or two weeks max, before I couldn't stand for more than 30 seconRAB. Again my experience taught me it had nothing to do with what you tried to do to help it, i.e. hot tub, heat, p.t. etc. but how I positioned myself physically. If I would lay flat on the floor I felt o.k. but could not stand, sit upright in chair, etc. I know I'm dribbling on here but, my point is, try to pay attention, and keep track of, not necessarily what he does to try to relieve pain, but how is he physically positioned when pain kicks in, and if you can notice a pattern, and kind of "turn pain on and off" with specific movements, then it sounRAB to me like he's got a problem with the sciatic nerve getting pinched.
I hope I am of some help.