Yes, it's quite possible he's barely heard of T1.
I was guilty of a similar assumption - that all adult cases of diabetes are Type 2. I went to high school with a boy with juvenile diabetes who did not survive high school. Probably to help us deal with it, it was conveyed that this was inevitable and typical. So somehow I took from this that T1 people were ALWAYS kids and that they NEVER lived beyond their teens. I looked with disbelief at anyone if they said, "I think he's a Type 1 diabetic" about an adult. "Not likely," I'd say. I was entirely clueless and ignored lots of evidence around me.
I know now this is patently false - now that I have prediabetes. I now understand that adult Type 1s, both those who've grown up with juvenile diabetes and the newly diagnosed, make up a large percentage of adults with diabetes. I've definitely had my world view corrected.
Before, I also had NO clue about the difference - that in one case, your beta cells are all but kaput, actually usually ARE kaput, and in the other, they've got considerably more oomph. Or about all the other, "newer" types of diabetes.
I'm not necessarily recommending this, but...if this happened to me and the boss was truly a friendly-minded one - and he sounds like he may be, just too immature to realize the legal implications of his position - I'd probably hand him a brochure that differentiates the diabetic types and gently correct him. (I have to admit, I've corrected nosy, misguided bosses more than once in my day in this shamelessly sneaky fashion.)
I would say something like:
"Hi! I thought you might find this interesting since you mentioned diabetes the other day. Let's see...Type 2...LADA...here we go. That's me." [I'd point to the words TYPE 1 on the brochure.] You mentioned bitter melon the other day. Unfortunately, it would have nothing to sink its teeth into with me. And if it did - even if I have a few beta cells that were rallying - using bitter melon would zonk them out completely if its action was to increase insulin production by the pancreas. Kind of like removing the bottom card in one of those houses of cards, you know? [Grin, giggle.]
"Of course, there's a chance it might reduce insulin resistance or act as an insulin mimetic, like many of the other natural supplements that are being investigated. Hey, that reminds me! I'm friends with several Type 2 diabetics - that's the one everyone calls 'adult onset.' THIS kind." [And I'd point to TYPE 2.] So I've learned some things about that kind of diabetic. I wanted to tell you, if you ever get diagnosed with Type 2, you might want to look into fenugreek or cinnamon as well as the bitter melon you mentioned - anecdotal evidence has been pretty promising. But if you do go with bitter melon, you might want to try supplements rather than the vegetable, because some people find it hard to stomach. So...where was I? Oh, yes...do you happen to know if bitter melon acts by promoting insulin production?" And then I'd look innocently at him with my techno-babble ringing in his ears.
Typically, such a boss would frown, "Um, I'm not sure. I'll try to find out," And I'd smile and say, "I'd appreciate that - I'm always interested because sometimes I think I know everything about my condition, but I find I'm always learning. I really think it's important to increase diabetes awareness. Did you know a lot of people are unaware that Type 1 even exists?" [Laugh and wrinkle nose.]
I've had good responses with this kind of thing. It's patronizing if you're "in the know", yes, but it's also role-reversal - making him acknowledge who the authority is here. (And your diabetes is YOUR territory, and YOU rule it, not the employer. You ARE the authority.) After having this kind of interaction (not about diabetes, obviously, but other things), I've ALWAYS had bosses and coworkers come away thinking they were best friends with me. It got me through some horrible bosses and was the ONLY way I could maintain any sense of strength when I was working in my "grunt" jobs.