Your family doctor and a nurse are not the medical team that should be determining what you need to treat your spine.
You need to be seeing a spine specialist. either an orthopedic surgeon who specializes in spines only or a neurosurgeon who specializes in spines only.
You need a complete evaluation by a spine specialist as to what is wrong with your husband's spine and what the best course of treatment is for what is wrong.
Physical therapy would help your husband to strengthen his core muscles that support the spine and body and may provide some pain relief, but will not widen the disc space.
I have seen and heard of doctors claiming that a patient has an extra vertebrae and they really don't. It is just the way the radiologist counts the vertebraes, on the other hand there are people that are born with an extra vertebrae.
To be properly treated, I urge you to seek the evaluation of a spine specialist and not the diagnosis and treatment from your family doctor and his/her nurse. They are untrained and unqualified to treat and diagnose spinal issues and really shouldn't be doing so, but rather sending you to a spine specialist.
Good luck and keep us posted.
Fran