How To Treat Spinal Fluid Leak Into Spinal Column Causing Difficulty To Walk?

My brother is experiencing decreased use of lower limbs. Muscle in both legs are atrophied. He can barely walk and is unable to do so without the use of a walker. Falling because of balance issues. He had surgery in June to his cervical spine. Doctor advised that he has spinal fluid leaking into spinal column. Recommended additional surgery because leak has progressed to thoracic spine. He is not in any pain before or after the surgery. I am belief that he needs a second opinion. No clear diagnosis provided but they have said that physical therapy is not going to improve his condition at this time.