Since this is a deteriorating condition, which came after taking Jardiance, report these side effects to the FDA at 1-800 FDA-1088.
I have had IVIG without incident for what was diagnosed as autoimmune related neuropathy, but it takes time to get it rolling through the medical pipeline. This needs a more accurate and specific diagnosis in my lay opinion.
Tick-borne illnesses should also not be ruled out.
I hope you get better answers for your mother. She deserves them, and so do you.