Without knowing the details of your uncle's surgeon nor surgery, in general, recovery after disc surgery depends on:
1. neck or back surgery (longer for neck)
2. fusion or non-fusion surgery (longer if fusion implants are used)
3. more than one disc or just single level (longer if multi-level surgery)
4. standard open surgery or minimally invasive approach (longer if larger incision wound e.g. minimal invasive single level lumbar disc surgery can be discharged the next day)
5. possible complications ocurring during or after surgery (longer if any) - this in turn depends on
a) your uncle's health/fitness for undergoing major surgery anaesthesia
b) your uncle's surgeon's years of experience/specialised training in spine surgery and whether he does minimally invasive surgery (if applicable) and whether the initial diagnosis for the surgery (e.g. slipped disc compressing his nerve) is completely eradicated by the surgeon without leaving any residual compression and with minimal collateral damage during the surgery
c) your uncle's recovery process during the first one month after his surgery in looking after his wound, his neck/back and his compliance in postoperative medications and rehab physio
Hence the common but important advice of going through all the abovementioned list of questions with his own surgeon individually and fully before consenting for surgery (assuming its not an emergency operation)