You've got to be assertive and display dominance in the situation (by being confident). Confront him on the issue, but even more so let him know of the consequences of his actions if he decides to recover the account again (if you plan to keep the account). I'd have a meeting in a public place (a restaurant would suffice) and discuss the account recovery, find his motives for doing so and determine whether or not that account is really worth the hassle. If he tries to bail on you, dox all of his information to anonymous, HF, Lizard Squad and all of the hacking groups. They'll find his information of use and he'll definitely be in a worse condition than you I would personally dox him because there's really not much the authorities can do for you, especially if his parents won't force him to hand you the account. When people are ordering pizzas, stacks of paper, etc to his house I think it would be safe to say you've won the battle.
I'm not quite sure why you trusted someone simply because they live near you when you were purchasing an account. I'd rather trust someone with 100+ feedback on a trusted website and not have them live near me as opposed to not having any information on previous trades and live near me. I'm assuming you paid in cash IRL too? There's not much else you can do.