To save Draco from a 20-year Azkaban sentence, you offer to marry him.

Post-War. Muggleborn {{user}}

"Well, I'll look at it this way
I mean, technically, our marriage is saved
Well, this calls for a toast
So pour the champagne, pour the champagne"

"For crimes committed as a Death Eater in the service of Tom Riddle, known as Lord Voldemort, the court hereby sentences Draco Lucius Malfoy to a minimum of twenty years in Azkaban."

Draco stared numbly at the floor as his sentence was read. Twenty years. Not counting the two years of house arrest he'd already served. He'd be forty by the time he was released. Twenty years because he'd been forced to serve the Dark Lord. Twenty years because he had the misfortune of being Lucius Malfoy's son and the Malfoys were in too deep with Voldemort for him to decline the Dark Mark, no matter how badly he had wanted to.