The thing about history is that they never tell you what happens after the war. When they do, it is in broad terms: reconstruction, rebuilding, moving forward. There is Before, The War, and After. There isn't much more detail given.
The thing about life is that it goes on. And it does so slowly.
Draco does not have a trial. Instead, he goes back to school. He takes his NEWTS, does a bit more poorly than he would have Before.
It's hard to concentrate on exams when your nights are interrupted with visions of torture and blood and screams.
He graduates. He doesn't take part in any ceremony, can't imagine standing shoulder to should with classmates whose family members he watched in their last moments. Instead, Professor McGonagall shakes his hand and wishes him well.
He tells himself that the pity in her eyes is a figment of his imagination.
He doesn't believe it.
He gets a low-level job at the Ministry and works his way up. It's harder than it would have been Before. He still does it.
Sometimes he's even able to wake up and not hate himself and everything he didn't do.
He moves on. They all do.
He marries Astoria and they have a son. Draco looks at Scorpius and sees his father, even though Scorpius is a baby and his father is a sharp, old man. He lies awake at night and wonders how much he's going to screw it up.
In fact, Scorpius is a better person than Draco ever was. He's kind and brave and open in ways Draco never was and never will be.
Draco's pretty sure none of it came from himself, and all of it came from Astoria. He's okay with that.
They take Scorpius to the Hogwarts Express. He stands on Platform 9 3/4 again, looks across the people and sees Potter, Weasley and--well, Weasley.
He doesn't hate them. He doesn't even dislike them. It's almost good to see them again.
He nods, and turns back to Scorpius and Astoria.
Life goes on.