In the early days of artificial disc replacements, the rehab program after LDR included bracing. Motion was limited for the first eight weeks. There was no sitting or bending allowed during this time.
Researchers reported a large number of patients ended up with complete ossification. This means the bone fused at that level, and motion was no longer possible.
With active PT starting at the end of the first week, this problem was eliminated. Early movement is now highly recommended to avoid cases of partial or complete fusion. Your husband will likely have better results after this surgery if he follows the rehab program.