Hypoglycemia is very different from Diabetes. Hypoglycemia is either A) a hypersensitivity to insulin being produced or B) unregulated insulin bursts combined with a lack of glucagon release from the liver. Insulin is the 'key' that unlocks the cell door and allows glucose from the bloodstream to enter to be used as nourishment. When there is too much insulin, or not enough glucose, is when the 'low' feeling comes on.
Theere are so many variable that can cause a low blood sugar reaction, sometimes it may seem that they come on for no apparent reason. In fact, a person who is well controlled will have random lows - we just always need to be aware and prepared.
People without hypoglycemia feel this reaction too - irritation, growling stomach, headaches, carb-cravings - but one with hypoglycemia cannot produce, or not enough of, the stored glucose on demad to fend off the low - disorientation, light-headedness, slurred speech, double vision.
Eating regular, smaller meals greatly reduces to chances of having a low blood sugar reaction. BTW - chocolate is not a good remedy for low blood sugar - the high fat content in chocolate prevents the sugar from rapidly disolving in your mouth where glucose is most readily absorbed. Fruit juice, hard candy, sweetend pop works within minutes then follow up with a carb/protein combo to keep it from falling again.
Diabetes (type 1) is a complete lack of insulin production and so one must balance the rules of hypoglycemia (low blood sugar) with injections of insulin to prevent hyperglycemia (high blood sugar). Low blood sugar is almost never fatal (unless, of course, it is caused intentionally with a massive overdose of insulin). Even becoming unconsious is the body's way of conserving energy to fuel the heart, lungs and core brain funtions. Eventually, the liver will begin the process to bring a person back to a concious level so that they can eat, but it is not enough to sustain any kind of activity (ie; walking, thinking, speaking coherently) and so one may require help at that point.
Hyperglycemia is what causes the long-term damage to diabetics - kidney funtion, heart problems, nerve damage, retinal neuropathy, etc. Hypoglyciamia is dangerous as it pertains to the immediate situation - driving, opertaing machinery, in danger of falling and hitting yourself on something, dropping something, losing a child by the hand (I have been in all of these situations and it is very scary) but the long term effect are short lived. of course there are alway exceptions to that rule. LOL I have a reaction so low, that I had a stroke (caused by lack of glucose to the brain) which was a fluke that I injected my insulin too close to a blood vessel. I lost my ability to speak and the only word I could formulate for days was **** due to extreme frustration.
I have had blood sugar readings of 1.5 (where, here in Canada, the range of 'normal' is 4-7) which is a barely functioning level, however, still walking and talking. I have also had them at 3-4 and not been able to carry a conversation. The body will adjust to a baseline level and when it becomes used to running at 10-13, 3-4 is very low. however, if my baseline is 4-6, then 2-3 is not out of scope for function.
Anyway - I hope this info helps you understand what you are seeing when your friend is in need of help.