You may not like my answer. I am a retired paramedic, with spine damage from my career. CABG surgery can result in lose of blood flow to the spinal cord, with permanent damage. Likely you dad and his legal representative signed paperwork acknowledging the risk. My other thought is that he had a bulging disc in his spine (back). Almost always, if they burst, the fluid leaks out, causing pain but no spinal cord damage (paralysis). Patient nearly always require surgery to fuse the spine, relieving pain and restoring function. It is rare but disc can burst inwards, damaging the spinal cord. It is possible during surgery it burst. I am not sure this is negligence on Kaiser part, let alone malpractice. He and his physician may not have been aware of any spine (back/neck) issues. You want to look for CT, MRI or PET scan reports.