What would you have said?

i would have told him just because my cjild needs insluin does'nt make him much different from other kids. he's not disabled, he's not challenged, he's a kid with a defective pancras

Throw in a little reality...as a T1D I have a disability, but I'm not disabled. The definition in the ADA focuses on the recognizing the endocrine disorder as a condition that can affect normal daily activities that may require accommodation to maintain normal function. That pretty much describes the big “D” and the daily challenges. I make accommodations to be "normal" throughout the day. 

Therefore in my mind, the reality is that I have a disability that I need to accommodated with insulin, food, knowledge, BG testing and my diabetic loaded brain.

Sounds like he just needed an education about calling your son as disabled person w/o knowing him and the he can do anything he wants, so no labeling is appropriate. I would have loaded him up with a T1D diabetic educational experience. Then asked him to donate to ADA and JDRF to get ride of this challenge in my life.