My autonomic neuropathy was one of my first major problems.

There are many tests for autonomic dysfunction...all depending on what your symptoms are (which you don't mention). Tilt table will determine whether there are any POTS or orthostatic hypotension affecting your heart rate or BP. There is also 24 hour BP monitoring as well as holter monitors for heart rate.

If you have GI problems, then gastric empty study is available.

There is QSART and skin biopsy to check for general autonomic fiber damage and/or sweat dysfunction.

Sure, you can die from autonomic neuropathy, but it all depends on your level of autonomic failure, the cause, symptoms, and tolerance for medications. But most people can find ways to manage their autonomic dysfunction with medication, life-style changes, etc.