I would tell the officer that the person is a diabetic, and instead of checking for an alcohol level they should be checking his insilin levels and hope for the best.

First I would check if I had my camera with me.      If so,  I would take a bunch of pictures and then give them to the guys wife.   

Maybe that way they can have a good lawsuit against the police/sheriff department.

 

And that way they can all get the training to better understand the difference between drunk and diabetis.