Welcome to the forum
While you may not experience diabetes in your own body, by being supportive to someone else you are making it easier on theirs.
There is a special person in my life, without her I would have found this way more difficult. I was only diagnosed a few weeks ago and she helped me to do even some basic thinsg, like remembering to test before bed or taking my lantus injection (24 hour). Also she knew about what foods I could eat before I did.
I am soon to start my British Sign Language Level 2, I am a hearie so I have had a small taste of not being directly effected by deadness or whatever else.
That being said, the people going through it may notice how they are restricted or limited by a disease but it is YOU who can see the changes in them. Subtleties that they themselves will miss, like when I have a cloudy mind due to high blood sugar levels, sometimes I don't notice but my lady friend can and makes a mental note of it.
Also there is also the perspective of there being insufficient information out there for the general public, who may or may not be effected by diabetes some day.
I have both of my parents who are diabetic and I knew virtually nothing about it, if you had asked me about it back before my diagnosis I would have been able to talk about a bunch of things but not actually with any degree of accuracy. Now I can, It isn't because I have the disease though, it is because I am motivated to learn.
One example that I feel is relevant is that, one of my interests is Hypnotherapy and I learned this in order to help someone I care about to get over sexual abuse. Being a guy pretty much limits my capacity for understanding what it is a woman would feel from such a trauma, but with time I had learned a great deal about it. I don't think I needed to know the depths of it in order to help, I knew enough to have a level of understanding that was of benefit. Biggest lesson I learned was to seperate my emotions from the situation, in the long run this has served me well for years since but also it helped her to deal with things better because I wasn't adding my own feelings into it. I wouldn't have known the importance of this if it wasn't for her explaining it to me.
Anyway, I have waffled on a fair amount, I haven't even finished reading your post actually (5am here and I feel a bit lazy to read), I will read the rest tomorrow probably.
In the meantime, welcome aboard, lots of lovely people here with useful information and experience. I have learned a great deal thanks to those people.