What is the role of Ty Simpkins(little boy from Iron Man 3 ) in Avengers:Endgame.

What is the role of Ty Simpkins(little boy from 

Iron Man 3

) in Avengers:Endgame.

The little boy Harley from Iron man 3 was also a tech geek, That means he was also highly interested in technology.
As per the movie, When tony stark's home was destroyed by the enemy the J.A.R.V.I.S.(his artificial intelligence) get him out from the sea to save his life and make a destination to hide on its own, That was near where the boy lived. Tony broke into the boy's garage and caught by the little boy. After a little while he helped ironman a bit, They even saved each other at time.

Don't worry this the the end of your waiting:

If anyone remembers the ending of Iron Man 3 - 

Tony Stark 

created a new workspace for the little boy on his garage. And in the movie AVENGERS:AGE OF ULTRON tony stark was talking about someone who hacked internet to defeat ultron, And tony travelled NEXUS(center of internet) to find out him and got failed. It is possible that he will help paper pots to find out Tony Stark and design a suit for as per the rumors about hulk-suit.