Somehow my ploy worked, and he called me up a few days later to tell me that his mother had bought him the guitar. I went over to his house and played it for a bit, then told him that I'd come over the following day and show him the rest of the song.
Unfortunately, that night, he was reading the owner's manual for the Tele and got to the part about removing the cover from the bridge pickup -- a simple matter of popping off the metal cover. Not understanding the difference between the pickups, he took a screwdriver and tried to remove the cover from the neck pickup, which was bolted to the scratch plate, and wound up destroying the guitar. He called me up the next day and told me about it. I never did teach him the rest of the song, but at least he stopped going out on his parents' pool deck and playing every afternoon. The neighbors should have thanked me.