Just to correct what Chunky said in humans type 2 with too high blood suger is treated either by diet or by tablets, only type 1 is treated with insulin.
Sorry I have only just caught up with this thread and am so sorry to hear that Mister is not well again. Your vet sounds like he is doing all the tests but am just wondering about the ears cos a virus that can cause these probs in humans can not been seen, not even on MRI scan........I know cos I am one! Also virus cannot be treated with anti biotics cos it burns itsself out, and in my case it caused damage in the ears which needed a special treatment.
I do hope that the reason for Misters wobblyness can be resolved quickly, cos it does sound a bit like he is dizzy or disoriented with him falling like that and an MRI scan would show and probs in the brain, which it sounds like it didnt which is great.
keeping my fingers crossed for Mister and you and hope this is solved really quick.