My chessie/lab mix had a ruptured disc and was paralyzed from the neck down for a week. It was a good thing that DH was out of town and I couldn't make "the decision" with out him, 'cause after heavy steroid dosages, Kahlua started to regain some sensation. Long story short, she stayed at the vet's until she could empty her bladder with out someone manipulating her bladder, and we did months of water therapy with her...but now she runs like a deer and only has a slight limp when walking. She has a bit of difficulty getting into/out of a sit or down, but is healthy and happy. Keeping her weight down is very important.
You probably will get a lot more advice and input if you post this recent problem in the Health forum.
Good luck and hope Rex is feeling better soon!