Good grief. Do the right thing, and pay the kid's parents if your legal department balks at cutting him a check directly.
But Paypal is such an awful company to its customers, what are the odds they'll do the right thing w.r.t. independent security researchers?
I hope this kid sues their pants off and gets attorney fees and triple damages if they balk at demanding payment. Any HN readers know any lawyers willing to take a case contingency or pro bono?
Or alternatively he could just sue in small claims court.