No boogers are not dead brain cells.
You wouldn't want any of your brain cells to die because then you'd eventually be brain dead because that's what happens when your brain cells die.
You need your brain cells alive to keep your brain healthy and for you to be able to think, move, talk, eat and just to live.
So boogers cannot be dead brain cells.
Boogers are just mucus that has dried out and hardened.
The mucus comes from your nostrils and is produced as a way to get rid of germs and bacteria.
I'm not sure where the name boogers came from but the name boogers has been around for many years and likely 100 years or more.
I guess someone came up with the name boogers to have a better name for mucus which is what boogers are.
Boogers are just mucus that is usually dried out and then you pick your boogers from your nose and some kids eat their boogers which is gross.
I admit I used to pick my boogers and eat my boogers until I was around 8 years old.
I then decided it was gross and stopped.