I am very lucky to have a best friend who, somehow -by osmosis maybe or just because she cares - has learned so much about D and totally gets it. In fact, she can recognize that I'm going low before I know it myself. When we were sitting shiva after my mom died, she came over with a cup of juice and said "test - I think you're going low (which I was) and then shooed everyone away while I ate. She reads everything she can about D and, more amazingly, she remembers it all.
Now that we're older and she is pre-diabetic, she has called me many times for advice re when to start taking oral meds, what to eliminate from her diet to lower her bg's/A1c's (she already exercises nearly every day and eats a very healthy diet), and she's managed to stay off meds for a couple of years.
I have a brother who also is insulin-dependent, and my mother was, too (from chemo...onset at age 65!), but other than those two, my family totally doesn't get it and neither do most of the other people I know.