What Happened to Harley?

After IM3, we never see Harley again until Endgame, at Tony's funeral. This got me thinking.
What happened to Harley after he met Tony?
Did he stand up to his bully?
Did he keep tabs on Tony, on Iron Man?
Did he look out of the window of his garage from time to time, wondering whether he would ever see him again?
Did he tell his sister all about the adventure he had, how he had gotten to help Tony Stark and defeat the Mandarin?
Did he see Tony was missing and wonder if he needed his help again?
Did he blip?
So, I decided to write some one-shots. Enjoy.