Redemption: The action of saving or being saved from sin, error, or evil.
Lets take a look a the the progression of Draco Malfoy throughout the books:
Books 1 - 5 : Ignorant, bigoted, selfish, spoiled. Draco lives a life of no consequences, anything he does wrong will be corrected by his father's money and / or influence.
Book 6: Suddenly his father is in prison. The protective bubble of a consequence-free life is shattered, and he is given a seemingly impossible task which will literally destroy his family if he fails. He is afraid of this new world.
Book 7: Things are becoming worse and worse for the Malfoys. It becomes obvious to Draco that Voldemort doesn't care about anyone. He begins to realize his family (and friends) are important to him, and that they won't be safe under Voldemort. Therefore he starts to change, he doesn't reveal Harry Potter, he tries to save his misguided friend (Crabbe). At the end the Malfoys defect from Voldemort's army, choosing family over (assumed) power.
I think this illustrates a lot of growing up that Draco experienced in his last two years in the books. He realized that friends and family (relationships) were important, at least important to him, and were more important than the supposed power under Voldemort.
Voldemort had no concept of family, friends, or love. All of his associates (with perhaps the exception of the insane Bellatrix) followed him out of fear, not out of admiration or affection. How long til Voldemort saw his lieutenants as potential threats? Along the same lines is a quote from Gandalf:
[Speaking of Sauron]...and he does not share power.
Draco and his family realized there was no future in Voldemort's world (a world of perpetual evil). So they had to turn away from it.
