I'm sory to hear that your husband is having so much trouble. I know what a difficult experience this is. May I ask what kind of surgery did your husband have? Was it a laminectomy? A discectomy? What level of the spine was involved? Was more than one disc affected?
I know from personal experience, it can take up to 18 months for nerves to fully regenerate after a spinal surgery or injury. I had 2 discectomies in my lumbar/sacral spine. One in 1988 and one in 1995. After the second operation I was temporally paralized in the left leg for a few months, and after that my leg would "give out" when it got "tired" for months afterward. My surgeon called this "nerve shock". But it stopped happening after about the 18 month period just like he said it would.
(Physical therapy to strengthen the muscles in that leg also worked wonders for me. )
The EMG tests were not pleasant, but not awful. At first it feels like someone is snapping a big rubber band against your skin. Then as they do the needle portion of the test it feels like novacaine injections at the dentist office. (You know the part before it gets numb)...not nice, but bearable.
Once the test is over, the pain doesn't hang around. When it's over, it's over. No soreness or anything, but you will probably want to drive him there and back anyway, just for the stress factor!
Good luck to him. I'm still suffering with a bad back all these years later. It's an awful thing..but then again he will never have to add pregnancies to his bad back! LOLOLOL!