Just wondering about what's going to happen to my brain when I die.

Your brain turns into mush when you die and dries up, leaving an empty cavity.

Depends on if you donate your brain to research or if you take it with you to the grave...

I mean, what is happening in the brain when someone is dying?

The brain can't function without blood and oxygen. As your heart slows down, your lungs slow down, decreasing oxygen and blood to your extremeties. No one knows for sure, but I imagine everything becomes foggy, unclear, functions decrease because no brain power. The heart can pump on, but the brain can be gone.

Who knows for sure. You only get a small glimpse if you are with a person while they are leaving you. I have often wondered too. Some day we will find out, eh ?