That sounds really difficult, I’m sorry you are going through this. 🙁
Did your vet consider EC (http://www.medirabbit.com/EN/Neurology/cuniculi/pyrimethamine.htm) when you took him in? It doesn’t often show up in tests but can cause neurological problems. Many vets will treat for it on suspicion alone, and given his neurological symptoms that would be my next step. It is thought that many bunnies carry it asymptomatically but then my show symptoms when the immune system is weakened (such as with age). If it is EC, it is treatable with a very inexpensive medication, but it can take time to work (at 28 day course). Since you just saw your vet and had a thorough exam, maybe you could call them and request them to give you a prescription to try (it’s also available otc, it’s a deworming medicine), but the vet should give you to the dosage. Usually it’s also given with an anti-inflammatory because some of the symptoms are due to inflammation.
The fact that he pulled through and started eating again means he’s a fighter.
.
.
.
The answers provided in this discussion are for general guideline purposes only. The information is not intended to diagnose or treat your pet. Seek the advice of your veterinarian or a qualified behaviorist.