But going too high can be dangerous. My sister is diabetic, and when she was very young and recently diagnosed (about 8) we accidentally sent her hyper (when we realised she was hypo), as opposed to hypo - it was not pretty at all. Surely if you're hyper, insulin would take you down and effectively make you a bit better? I don't know the situation here at all, but I know how scary it can get when you don't know what you're doing. Maybe that was the case here. Or maybe he didn't have a blood test kit on him, or they wouldn't allow him to do a blood test because they thought he was lying. Or a number of other reasons. All I'm saying is there's not enough evidence to rule it out either way.
You can give a diabetic too much insulin, and it will cause hypoglycemia. Hypoglycemia equals low blood sugar. Hyperglycemia is high blood sugar. Everytime I have overdoped on glucose, it did not cause convulsions, it caused drunken, feeble behavior. In fact, one can resemble an intoxicated person so well that I was educated to inform any law enforcement officer of my diabetes. High blood sugar can cause one to give a false postive on a breathalyzer test. High blood sugar dosen't cause convulsions.
NOT giving a diabetic insulin doesn't cause convulsions. It can cause you to fall out, though.
As for a glucose meter and sharps, teh kit itself shouldn't be where prisoners can easily access it.
If he were worried about his diabetes, then he shouldn't have robbed a house and bitten a police dog. Then he wouldn't have landed in jail. I feel no pity for this guy.