My Dear Sleeblurk,
I have noted for some time your indolence concerning long-term degradation of your patient. As any learned devil knows, this kind of devilish working is most crucial in ensuring places in Our Father's House.
Your patient is at the ideal age for certain kind of temptations to be put into play that would work into the destruction of his morality. His parents, both lost to the Enemy (and whose designated devils have paid dearly), effectively shut him off from the society on Earth for much of his childhood. This, in turn, allowed your patient no shield from the splendid influence of the long-damned populace of his peers, and the mediums that influenced them. I'm speaking, of course, of the prime source of temptation known as public high school.
Therefore, Sleeblurk, you must act quickly and with a sure fist. Your patient has a great deal of this "charisma" that attracts humans like flies to a corpse, and will surely be tempted by his peers. His first thought will be to remember what his parents have taught him; it will be up to you to remind him that his primary goal at school is to make certain the approval of his peers and the maintenance of his reputation that he has worked so hard on over the entirety of his school years.
However, you must remember to distract him from any pangs of conscience before temptation comes; for, if he learns of what may tempt him beforehand, he will be sure not to give in and will hold this idea firm in his mind until those possible temptations are past. On-the-spot decisions favor us more often than premeditated decisions.
I look forward to seeing how you go about this process. Remember that damnation begins in the youth,
Your Affectionate Great-Uncle,
Screwtape