Although bugs crawl around in your ears there's no way for the bug to crawl in your ear and go through your brain.
Your ears are connected to your brain but there's not a tunnel from your ears to your brain for the bugs to crawl into through.
So it's not possible for bugs or any other insects to crawl up through your ear and into your brain.
If a bug or other insect does crawl into your ear they might bite you and cause an infection in your ear but the bug will not be able to reach your brain.
My brother used to tell me that when I was a kid and I believed him and got scared when I was around 5 years old.
But it's not true and now I laugh about it.