Okay kiddo, do you know what your brain does? It helps your body do everything! It tells your heart to beat, your lungs to breathe, and helps you move and think. So when someone's brain is no longer working, it can be really serious.
When all parts of the brain stop working, including the brainstem, that means someone is brainstem dead. The brainstem is like the boss of all the other parts of the brain. It controls important stuff like breathing and heartbeat. So if someone's brainstem dies, their body won't be able to work properly anymore.
If a doctor thinks someone might be brainstem dead, they will do a bunch of tests to check the person's brain function. They'll shine a light in their eyes, poke them with a needle, and even give them a cold drink to see if their body reacts. If the person doesn't react to these tests, it's a sign that their brainstem might not be working anymore.
If the doctors confirm that someone is brainstem dead, that means they can't live without help from machines that breathe for them and pump their blood. It's really sad, but it's important to know so that we can make sure the person can't feel any pain and we can comfort their loved ones.