you have asked 3 questions here-
1)the memory can be brought back but the success depends on the amount of injury
to the nerve cells.but as you have mentioned that the nerve cells have "died",i find it very difficult practically to say that the memory would come back if the information provided by you is what actually is scenario.i find the information inadequate and also the language used by a non medico may present a complete different picture,so i would suggest you to enclose the reports along with.
2)you haven't mentioned at which level disc prolapse
has occured.also it depends on the severity of disc prolapse.seeing your anxiety
i would like to assure you that its very unlikely that due to disc prolapse the person remains on chair whole life.in fact rest is no more taken into account while treating disc prolapse.he is undergoing operation indicates that the prolapse was of higher degree which couldn't be managed with physiotherapy
.but the purpose of operation is to put the disc back on space.BUT POST OPERATION DON'T EXPECT THE PERSON TO HAVE A LIFE EXACTLY THE WAY IT WAS EARLIER THOUGH FEW CASES HAVE BEEN REPORTED OTHERWISE.I HIGHLY RECOMMEND LOWER BACK STRENGTHENING EXERCISES POST 6 MONTHS OF OPERATION.that would take care a lot.
3)operation is a stressful condition post which the immune power of body decreases to alarming extent.the immune level can be checked by seeing the blood picture.just make sure to add lots of beta carotene(vit.A),vit.c,zinc,vit.K,B vitamins
,vit.D and calcium,and if possible L-glutamine and arginine
.AVOID VIT.E AND HERBAL SUPPLEMENTS AS THEY MAY CAUSE HEMATOMA
start atleast 10 days prior to surgery.surgical nutrition is important but simple.:)