How to announce to little bro

So my little brother is 10, and he means so much to me. I wanna do something really meaningful to tell him he's gonna be an uncle!!

The problem is, I dont know where to start 😭

I had a false positive last December and he found out then when I told my parents. This time my parents know, but I told them not to tell my little bro just in case something happens.

ideas anyone?

he's really Into cars, transformers, kinda into star wars, likes Pokemon, things like that. you know, typical 10 year old boy stuff.