My granny is 73 year old and she had spinal implant .. she can’t walk, she can not sit, she can only lay down..she had 37 stitches in her back but after having the operation, after 3-4 days her diabetes level goes down and suddenly then she behaves like she is mad; she just starts screaming, getting up, hurting herself, crying. After sometime she goes back to normal and after few hours she does the same things again.
Really we can have utterly zero idea what is happening with your grandmother and this is something now to discuss with her MD as to what procedure was done, what the plan is for rehab and recovery and what her prognosis is. Sure do wish you the best.