B12 deficiency is unlikely. There are blood tests however that can reveal this. I do not have the luxury of examining your father but if he has long tract signs (as I indicated earlier) with the current symptoms you have indicated and the MRI findings that I reviewed, I tend to agree with the surgeon who thinks that decompression of the cord would be helpful.
Donald Corenman, MD, DC is a highly-regarded spine surgeon, considered an expert in the area of neck and back pain. Trained as both a Medical Doctor and Doctor of Chiropractic, Dr. Corenman earned academic appointments as Clinical Assistant Professor and Assistant Professor of Orthopaedic Surgery at the University of Colorado Health Sciences Center, and his research on spine surgery and rehabilitation has resulted in the publication of multiple peer-reviewed articles and two books.