Forgot Title Name

Children’s book
Has a boy who grew too fast and his heart couldn’t handle it so he died
Built a model rocket with his friends
Always said the rocket would reach the moon

Do you happen to know if this was fictional? And was the boy the main character?

Closest I can see is a book called Squint by Chad Morris. It doesn't mention a rocket but one of the characters has a brother with progeria. It's fairly new, just 2018. Does that sound familiar?