If you consider Cursed Child canon, then Draco has changed.
Petra is right, Draco was jealous of Harry. He was popular at Hogwarts because of his scar + the teachers all like him. He lost his parents, he doesn't have a family who accepts him (Dursleys all hate him) so he's not had a happy life but at least he was very well-loved by people who aren't related to him.
