I am brittle diabetic. I just got on pump. I have very low bs occasionally. My sister died from low bs. When should I use glucagon?

Severe low. Glucagon should be used for severe lows, which basically means when you can't think clearly and can't eat/drink sugars to raise your blood sugar. This means only ppl around you can use glucagon (bc you'd be too confused to do so) - make sure close family and friends know where u keep glucagon and how to use it. If anyone needs to use it, u also need to see dr after.
Never. If you're awake & alert enough to use glucagon, you don't need it. Eat or drink something instead. Glucagon is intended to be used by someone else when a low sugar episode is so severe that you can't speak properly, and can't swallow safely enough to make sure food and liquid goes into the esophagus (food tube) and not into the trachea (windpipe).